[PATCH] drm: Extract drm_vblank.[hc]

Stefan Agner stefan at agner.ch
Wed May 31 17:51:11 UTC 2017


On 2017-05-31 02:21, Daniel Vetter wrote:
> drm_irq.c contains both the irq helper library (optional) and the
> vblank support (optional, but part of the modeset uapi, and doesn't
> require the use of the irq helpers at all.
> 
> Split this up for more clarity of the scope of the individual bits.
> 
> v2: Move misplaced hunks to this patch (Stefan).
> 

Looks good to me:

Reviewed-by: Stefan Agner <stefan at agner.ch>

--
Stefan

> Cc: Stefan Agner <stefan at agner.ch>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  Documentation/gpu/drm-internals.rst |    9 +
>  Documentation/gpu/drm-kms.rst       |    4 +-
>  drivers/gpu/drm/Makefile            |    2 +-
>  drivers/gpu/drm/drm_internal.h      |    3 +-
>  drivers/gpu/drm/drm_irq.c           | 1623 +---------------------------------
>  drivers/gpu/drm/drm_vblank.c        | 1645 +++++++++++++++++++++++++++++++++++
>  include/drm/drmP.h                  |    5 +-
>  include/drm/drm_file.h              |    1 +
>  include/drm/drm_irq.h               |  158 +---
>  include/drm/drm_prime.h             |    2 +
>  include/drm/drm_vblank.h            |  181 ++++
>  11 files changed, 1869 insertions(+), 1764 deletions(-)
>  create mode 100644 drivers/gpu/drm/drm_vblank.c
>  create mode 100644 include/drm/drm_vblank.h
> 
> diff --git a/Documentation/gpu/drm-internals.rst
> b/Documentation/gpu/drm-internals.rst
> index d218dd29221a..dd28e39cf966 100644
> --- a/Documentation/gpu/drm-internals.rst
> +++ b/Documentation/gpu/drm-internals.rst
> @@ -204,6 +204,15 @@ drm_device <drm_device>` irq_enabled field to 1 upon
>  registration of the IRQs, and clear it to 0 after unregistering the
>  IRQs.
>  
> +IRQ Helper Library
> +~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_irq.c
> +   :doc: irq helpers
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_irq.c
> +   :export:
> +
>  Memory Manager Initialization
>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>  
> diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
> index bfecd21a8cdf..2d77c9580164 100644
> --- a/Documentation/gpu/drm-kms.rst
> +++ b/Documentation/gpu/drm-kms.rst
> @@ -612,8 +612,8 @@ operation handler.
>  Vertical Blanking and Interrupt Handling Functions Reference
>  ------------------------------------------------------------
>  
> -.. kernel-doc:: include/drm/drm_irq.h
> +.. kernel-doc:: include/drm/drm_vblank.h
>     :internal:
>  
> -.. kernel-doc:: drivers/gpu/drm/drm_irq.c
> +.. kernel-doc:: drivers/gpu/drm/drm_vblank.c
>     :export:
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index c156fecfb362..acc88942c2e5 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -16,7 +16,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
>  		drm_framebuffer.o drm_connector.o drm_blend.o \
>  		drm_encoder.o drm_mode_object.o drm_property.o \
>  		drm_plane.o drm_color_mgmt.o drm_print.o \
> -		drm_dumb_buffers.o drm_mode_config.o
> +		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o
>  
>  drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
>  drm-$(CONFIG_DRM_VM) += drm_vm.o
> diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
> index bca2c66c5d28..6a0cbcc84534 100644
> --- a/drivers/gpu/drm/drm_internal.h
> +++ b/drivers/gpu/drm/drm_internal.h
> @@ -54,8 +54,9 @@ int drm_name_info(struct seq_file *m, void *data);
>  int drm_clients_info(struct seq_file *m, void* data);
>  int drm_gem_name_info(struct seq_file *m, void *data);
>  
> -/* drm_irq.c */
> +/* drm_vblank.c */
>  extern unsigned int drm_timestamp_monotonic;
> +void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe);
>  
>  /* IOCTLS */
>  int drm_wait_vblank(struct drm_device *dev, void *data,
> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> index c7debaad67f8..28d736c3fcb4 100644
> --- a/drivers/gpu/drm/drm_irq.c
> +++ b/drivers/gpu/drm/drm_irq.c
> @@ -3,6 +3,25 @@
>   *
>   * \author Rickard E. (Rik) Faith <faith at valinux.com>
>   * \author Gareth Hughes <gareth at valinux.com>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
>   */
>  
>  /*
> @@ -32,429 +51,15 @@
>   * OTHER DEALINGS IN THE SOFTWARE.
>   */
>  
> +#include <drm/drm_irq.h>
>  #include <drm/drmP.h>
> -#include "drm_trace.h"
> -#include "drm_internal.h"
>  
>  #include <linux/interrupt.h>	/* For task queue support */
> -#include <linux/slab.h>
>  
>  #include <linux/vgaarb.h>
>  #include <linux/export.h>
>  
> -/* Retry timestamp calculation up to 3 times to satisfy
> - * drm_timestamp_precision before giving up.
> - */
> -#define DRM_TIMESTAMP_MAXRETRIES 3
> -
> -/* Threshold in nanoseconds for detection of redundant
> - * vblank irq in drm_handle_vblank(). 1 msec should be ok.
> - */
> -#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
> -
> -static bool
> -drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
> -			  struct timeval *tvblank, bool in_vblank_irq);
> -
> -static unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */
> -
> -/*
> - * Default to use monotonic timestamps for wait-for-vblank and page-flip
> - * complete events.
> - */
> -unsigned int drm_timestamp_monotonic = 1;
> -
> -static int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */
> -
> -module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
> -module_param_named(timestamp_precision_usec, drm_timestamp_precision,
> int, 0600);
> -module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
> -MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable
> [msecs] (0: never disable, <0: disable immediately)");
> -MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
> -MODULE_PARM_DESC(timestamp_monotonic, "Use monotonic timestamps");
> -
> -static void store_vblank(struct drm_device *dev, unsigned int pipe,
> -			 u32 vblank_count_inc,
> -			 struct timeval *t_vblank, u32 last)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -
> -	assert_spin_locked(&dev->vblank_time_lock);
> -
> -	vblank->last = last;
> -
> -	write_seqlock(&vblank->seqlock);
> -	vblank->time = *t_vblank;
> -	vblank->count += vblank_count_inc;
> -	write_sequnlock(&vblank->seqlock);
> -}
> -
> -/*
> - * "No hw counter" fallback implementation of .get_vblank_counter() hook,
> - * if there is no useable hardware frame counter available.
> - */
> -static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
> -{
> -	WARN_ON_ONCE(dev->max_vblank_count != 0);
> -	return 0;
> -}
> -
> -static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
> -{
> -	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> -		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> -
> -		if (crtc->funcs->get_vblank_counter)
> -			return crtc->funcs->get_vblank_counter(crtc);
> -	}
> -
> -	if (dev->driver->get_vblank_counter)
> -		return dev->driver->get_vblank_counter(dev, pipe);
> -
> -	return drm_vblank_no_hw_counter(dev, pipe);
> -}
> -
> -/*
> - * Reset the stored timestamp for the current vblank count to correspond
> - * to the last vblank occurred.
> - *
> - * Only to be called from drm_crtc_vblank_on().
> - *
> - * Note: caller must hold &drm_device.vbl_lock since this reads & writes
> - * device vblank fields.
> - */
> -static void drm_reset_vblank_timestamp(struct drm_device *dev,
> unsigned int pipe)
> -{
> -	u32 cur_vblank;
> -	bool rc;
> -	struct timeval t_vblank;
> -	int count = DRM_TIMESTAMP_MAXRETRIES;
> -
> -	spin_lock(&dev->vblank_time_lock);
> -
> -	/*
> -	 * sample the current counter to avoid random jumps
> -	 * when drm_vblank_enable() applies the diff
> -	 */
> -	do {
> -		cur_vblank = __get_vblank_counter(dev, pipe);
> -		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
> -	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
> -
> -	/*
> -	 * Only reinitialize corresponding vblank timestamp if high-precision query
> -	 * available and didn't fail. Otherwise reinitialize delayed at next vblank
> -	 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
> -	 */
> -	if (!rc)
> -		t_vblank = (struct timeval) {0, 0};
> -
> -	/*
> -	 * +1 to make sure user will never see the same
> -	 * vblank counter value before and after a modeset
> -	 */
> -	store_vblank(dev, pipe, 1, &t_vblank, cur_vblank);
> -
> -	spin_unlock(&dev->vblank_time_lock);
> -}
> -
> -/*
> - * Call back into the driver to update the appropriate vblank counter
> - * (specified by @pipe).  Deal with wraparound, if it occurred, and
> - * update the last read value so we can deal with wraparound on the next
> - * call if necessary.
> - *
> - * Only necessary when going from off->on, to account for frames we
> - * didn't get an interrupt for.
> - *
> - * Note: caller must hold &drm_device.vbl_lock since this reads & writes
> - * device vblank fields.
> - */
> -static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
> -				    bool in_vblank_irq)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	u32 cur_vblank, diff;
> -	bool rc;
> -	struct timeval t_vblank;
> -	int count = DRM_TIMESTAMP_MAXRETRIES;
> -	int framedur_ns = vblank->framedur_ns;
> -
> -	/*
> -	 * Interrupts were disabled prior to this call, so deal with counter
> -	 * wrap if needed.
> -	 * NOTE!  It's possible we lost a full dev->max_vblank_count + 1 events
> -	 * here if the register is small or we had vblank interrupts off for
> -	 * a long time.
> -	 *
> -	 * We repeat the hardware vblank counter & timestamp query until
> -	 * we get consistent results. This to prevent races between gpu
> -	 * updating its hardware counter while we are retrieving the
> -	 * corresponding vblank timestamp.
> -	 */
> -	do {
> -		cur_vblank = __get_vblank_counter(dev, pipe);
> -		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq);
> -	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
> -
> -	if (dev->max_vblank_count != 0) {
> -		/* trust the hw counter when it's around */
> -		diff = (cur_vblank - vblank->last) & dev->max_vblank_count;
> -	} else if (rc && framedur_ns) {
> -		const struct timeval *t_old;
> -		u64 diff_ns;
> -
> -		t_old = &vblank->time;
> -		diff_ns = timeval_to_ns(&t_vblank) - timeval_to_ns(t_old);
> -
> -		/*
> -		 * Figure out how many vblanks we've missed based
> -		 * on the difference in the timestamps and the
> -		 * frame/field duration.
> -		 */
> -		diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
> -
> -		if (diff == 0 && in_vblank_irq)
> -			DRM_DEBUG_VBL("crtc %u: Redundant vblirq ignored."
> -				      " diff_ns = %lld, framedur_ns = %d)\n",
> -				      pipe, (long long) diff_ns, framedur_ns);
> -	} else {
> -		/* some kind of default for drivers w/o accurate vbl timestamping */
> -		diff = in_vblank_irq ? 1 : 0;
> -	}
> -
> -	/*
> -	 * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
> -	 * interval? If so then vblank irqs keep running and it will likely
> -	 * happen that the hardware vblank counter is not trustworthy as it
> -	 * might reset at some point in that interval and vblank timestamps
> -	 * are not trustworthy either in that interval. Iow. this can result
> -	 * in a bogus diff >> 1 which must be avoided as it would cause
> -	 * random large forward jumps of the software vblank counter.
> -	 */
> -	if (diff > 1 && (vblank->inmodeset & 0x2)) {
> -		DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u"
> -			      " due to pre-modeset.\n", pipe, diff);
> -		diff = 1;
> -	}
> -
> -	DRM_DEBUG_VBL("updating vblank count on crtc %u:"
> -		      " current=%u, diff=%u, hw=%u hw_last=%u\n",
> -		      pipe, vblank->count, diff, cur_vblank, vblank->last);
> -
> -	if (diff == 0) {
> -		WARN_ON_ONCE(cur_vblank != vblank->last);
> -		return;
> -	}
> -
> -	/*
> -	 * Only reinitialize corresponding vblank timestamp if high-precision query
> -	 * available and didn't fail, or we were called from the vblank interrupt.
> -	 * Otherwise reinitialize delayed at next vblank interrupt and assign 0
> -	 * for now, to mark the vblanktimestamp as invalid.
> -	 */
> -	if (!rc && in_vblank_irq)
> -		t_vblank = (struct timeval) {0, 0};
> -
> -	store_vblank(dev, pipe, diff, &t_vblank, cur_vblank);
> -}
> -
> -static u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return 0;
> -
> -	return vblank->count;
> -}
> -
> -/**
> - * drm_accurate_vblank_count - retrieve the master vblank counter
> - * @crtc: which counter to retrieve
> - *
> - * This function is similar to @drm_crtc_vblank_count but this
> - * function interpolates to handle a race with vblank irq's.
> - *
> - * This is mostly useful for hardware that can obtain the scanout
> - * position, but doesn't have a frame counter.
> - */
> -u32 drm_accurate_vblank_count(struct drm_crtc *crtc)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	unsigned int pipe = drm_crtc_index(crtc);
> -	u32 vblank;
> -	unsigned long flags;
> -
> -	WARN(!dev->driver->get_vblank_timestamp,
> -	     "This function requires support for accurate vblank timestamps.");
> -
> -	spin_lock_irqsave(&dev->vblank_time_lock, flags);
> -
> -	drm_update_vblank_count(dev, pipe, false);
> -	vblank = drm_vblank_count(dev, pipe);
> -
> -	spin_unlock_irqrestore(&dev->vblank_time_lock, flags);
> -
> -	return vblank;
> -}
> -EXPORT_SYMBOL(drm_accurate_vblank_count);
> -
> -static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
> -{
> -	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> -		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> -
> -		if (crtc->funcs->disable_vblank) {
> -			crtc->funcs->disable_vblank(crtc);
> -			return;
> -		}
> -	}
> -
> -	dev->driver->disable_vblank(dev, pipe);
> -}
> -
> -/*
> - * Disable vblank irq's on crtc, make sure that last vblank count
> - * of hardware and corresponding consistent software vblank counter
> - * are preserved, even if there are any spurious vblank irq's after
> - * disable.
> - */
> -static void vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	unsigned long irqflags;
> -
> -	assert_spin_locked(&dev->vbl_lock);
> -
> -	/* Prevent vblank irq processing while disabling vblank irqs,
> -	 * so no updates of timestamps or count can happen after we've
> -	 * disabled. Needed to prevent races in case of delayed irq's.
> -	 */
> -	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
> -
> -	/*
> -	 * Only disable vblank interrupts if they're enabled. This avoids
> -	 * calling the ->disable_vblank() operation in atomic context with the
> -	 * hardware potentially runtime suspended.
> -	 */
> -	if (vblank->enabled) {
> -		__disable_vblank(dev, pipe);
> -		vblank->enabled = false;
> -	}
> -
> -	/*
> -	 * Always update the count and timestamp to maintain the
> -	 * appearance that the counter has been ticking all along until
> -	 * this time. This makes the count account for the entire time
> -	 * between drm_crtc_vblank_on() and drm_crtc_vblank_off().
> -	 */
> -	drm_update_vblank_count(dev, pipe, false);
> -
> -	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
> -}
> -
> -static void vblank_disable_fn(unsigned long arg)
> -{
> -	struct drm_vblank_crtc *vblank = (void *)arg;
> -	struct drm_device *dev = vblank->dev;
> -	unsigned int pipe = vblank->pipe;
> -	unsigned long irqflags;
> -
> -	spin_lock_irqsave(&dev->vbl_lock, irqflags);
> -	if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
> -		DRM_DEBUG("disabling vblank on crtc %u\n", pipe);
> -		vblank_disable_and_save(dev, pipe);
> -	}
> -	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> -}
> -
> -/**
> - * drm_vblank_cleanup - cleanup vblank support
> - * @dev: DRM device
> - *
> - * This function cleans up any resources allocated in drm_vblank_init.
> - */
> -void drm_vblank_cleanup(struct drm_device *dev)
> -{
> -	unsigned int pipe;
> -
> -	/* Bail if the driver didn't call drm_vblank_init() */
> -	if (dev->num_crtcs == 0)
> -		return;
> -
> -	for (pipe = 0; pipe < dev->num_crtcs; pipe++) {
> -		struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -
> -		WARN_ON(READ_ONCE(vblank->enabled) &&
> -			drm_core_check_feature(dev, DRIVER_MODESET));
> -
> -		del_timer_sync(&vblank->disable_timer);
> -	}
> -
> -	kfree(dev->vblank);
> -
> -	dev->num_crtcs = 0;
> -}
> -EXPORT_SYMBOL(drm_vblank_cleanup);
> -
> -/**
> - * drm_vblank_init - initialize vblank support
> - * @dev: DRM device
> - * @num_crtcs: number of CRTCs supported by @dev
> - *
> - * This function initializes vblank support for @num_crtcs display pipelines.
> - *
> - * Returns:
> - * Zero on success or a negative error code on failure.
> - */
> -int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
> -{
> -	int ret = -ENOMEM;
> -	unsigned int i;
> -
> -	spin_lock_init(&dev->vbl_lock);
> -	spin_lock_init(&dev->vblank_time_lock);
> -
> -	dev->num_crtcs = num_crtcs;
> -
> -	dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
> -	if (!dev->vblank)
> -		goto err;
> -
> -	for (i = 0; i < num_crtcs; i++) {
> -		struct drm_vblank_crtc *vblank = &dev->vblank[i];
> -
> -		vblank->dev = dev;
> -		vblank->pipe = i;
> -		init_waitqueue_head(&vblank->queue);
> -		setup_timer(&vblank->disable_timer, vblank_disable_fn,
> -			    (unsigned long)vblank);
> -		seqlock_init(&vblank->seqlock);
> -	}
> -
> -	DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
> -
> -	/* Driver specific high-precision vblank timestamping supported? */
> -	if (dev->driver->get_vblank_timestamp)
> -		DRM_INFO("Driver supports precise vblank timestamp query.\n");
> -	else
> -		DRM_INFO("No driver support for vblank timestamp query.\n");
> -
> -	/* Must have precise timestamping for reliable vblank instant disable */
> -	if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
> -		dev->vblank_disable_immediate = false;
> -		DRM_INFO("Setting vblank_disable_immediate to false because "
> -			 "get_vblank_timestamp == NULL\n");
> -	}
> -
> -	return 0;
> -
> -err:
> -	dev->num_crtcs = 0;
> -	return ret;
> -}
> -EXPORT_SYMBOL(drm_vblank_init);
> +#include "drm_internal.h"
>  
>  /**
>   * drm_irq_install - install IRQ handler
> @@ -571,7 +176,7 @@ int drm_irq_uninstall(struct drm_device *dev)
>  
>  			WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));
>  
> -			vblank_disable_and_save(dev, i);
> +			drm_vblank_disable_and_save(dev, i);
>  			wake_up(&vblank->queue);
>  		}
>  		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> @@ -634,1187 +239,3 @@ int drm_legacy_irq_control(struct drm_device
> *dev, void *data,
>  		return -EINVAL;
>  	}
>  }
> -
> -/**
> - * drm_calc_timestamping_constants - calculate vblank timestamp constants
> - * @crtc: drm_crtc whose timestamp constants should be updated.
> - * @mode: display mode containing the scanout timings
> - *
> - * Calculate and store various constants which are later
> - * needed by vblank and swap-completion timestamping, e.g,
> - * by drm_calc_vbltimestamp_from_scanoutpos(). They are
> - * derived from CRTC's true scanout timing, so they take
> - * things like panel scaling or other adjustments into account.
> - */
> -void drm_calc_timestamping_constants(struct drm_crtc *crtc,
> -				     const struct drm_display_mode *mode)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	unsigned int pipe = drm_crtc_index(crtc);
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	int linedur_ns = 0, framedur_ns = 0;
> -	int dotclock = mode->crtc_clock;
> -
> -	if (!dev->num_crtcs)
> -		return;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return;
> -
> -	/* Valid dotclock? */
> -	if (dotclock > 0) {
> -		int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
> -
> -		/*
> -		 * Convert scanline length in pixels and video
> -		 * dot clock to line duration and frame duration
> -		 * in nanoseconds:
> -		 */
> -		linedur_ns  = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
> -		framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
> -
> -		/*
> -		 * Fields of interlaced scanout modes are only half a frame duration.
> -		 */
> -		if (mode->flags & DRM_MODE_FLAG_INTERLACE)
> -			framedur_ns /= 2;
> -	} else
> -		DRM_ERROR("crtc %u: Can't calculate constants, dotclock = 0!\n",
> -			  crtc->base.id);
> -
> -	vblank->linedur_ns  = linedur_ns;
> -	vblank->framedur_ns = framedur_ns;
> -	vblank->hwmode = *mode;
> -
> -	DRM_DEBUG("crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
> -		  crtc->base.id, mode->crtc_htotal,
> -		  mode->crtc_vtotal, mode->crtc_vdisplay);
> -	DRM_DEBUG("crtc %u: clock %d kHz framedur %d linedur %d\n",
> -		  crtc->base.id, dotclock, framedur_ns, linedur_ns);
> -}
> -EXPORT_SYMBOL(drm_calc_timestamping_constants);
> -
> -/**
> - * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
> - * @dev: DRM device
> - * @pipe: index of CRTC whose vblank timestamp to retrieve
> - * @max_error: Desired maximum allowable error in timestamps (nanosecs)
> - *             On return contains true maximum error of timestamp
> - * @vblank_time: Pointer to struct timeval which should receive the timestamp
> - * @in_vblank_irq:
> - *     True when called from drm_crtc_handle_vblank().  Some drivers
> - *     need to apply some workarounds for gpu-specific vblank irq quirks
> - *     if flag is set.
> - *
> - * Implements calculation of exact vblank timestamps from given
> drm_display_mode
> - * timings and current video scanout position of a CRTC. This can be
> called from
> - * within get_vblank_timestamp() implementation of a kms driver to
> implement the
> - * actual timestamping.
> - *
> - * Should return timestamps conforming to the OML_sync_control OpenML
> - * extension specification. The timestamp corresponds to the end of
> - * the vblank interval, aka start of scanout of topmost-leftmost display
> - * pixel in the following video frame.
> - *
> - * Requires support for optional dev->driver->get_scanout_position()
> - * in kms driver, plus a bit of setup code to provide a drm_display_mode
> - * that corresponds to the true scanout timing.
> - *
> - * The current implementation only handles standard video modes. It
> - * returns as no operation if a doublescan or interlaced video mode is
> - * active. Higher level code is expected to handle this.
> - *
> - * This function can be used to implement the &drm_driver.get_vblank_timestamp
> - * directly, if the driver implements the
> &drm_driver.get_scanout_position hook.
> - *
> - * Note that atomic drivers must call drm_calc_timestamping_constants() before
> - * enabling a CRTC. The atomic helpers already take care of that in
> - * drm_atomic_helper_update_legacy_modeset_state().
> - *
> - * Returns:
> - *
> - * Returns true on success, and false on failure, i.e. when no accurate
> - * timestamp could be acquired.
> - */
> -bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
> -					   unsigned int pipe,
> -					   int *max_error,
> -					   struct timeval *vblank_time,
> -					   bool in_vblank_irq)
> -{
> -	struct timeval tv_etime;
> -	ktime_t stime, etime;
> -	bool vbl_status;
> -	struct drm_crtc *crtc;
> -	const struct drm_display_mode *mode;
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	int vpos, hpos, i;
> -	int delta_ns, duration_ns;
> -
> -	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> -		return false;
> -
> -	crtc = drm_crtc_from_index(dev, pipe);
> -
> -	if (pipe >= dev->num_crtcs || !crtc) {
> -		DRM_ERROR("Invalid crtc %u\n", pipe);
> -		return false;
> -	}
> -
> -	/* Scanout position query not supported? Should not happen. */
> -	if (!dev->driver->get_scanout_position) {
> -		DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
> -		return false;
> -	}
> -
> -	if (drm_drv_uses_atomic_modeset(dev))
> -		mode = &vblank->hwmode;
> -	else
> -		mode = &crtc->hwmode;
> -
> -	/* If mode timing undefined, just return as no-op:
> -	 * Happens during initial modesetting of a crtc.
> -	 */
> -	if (mode->crtc_clock == 0) {
> -		DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
> -		WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
> -
> -		return false;
> -	}
> -
> -	/* Get current scanout position with system timestamp.
> -	 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
> -	 * if single query takes longer than max_error nanoseconds.
> -	 *
> -	 * This guarantees a tight bound on maximum error if
> -	 * code gets preempted or delayed for some reason.
> -	 */
> -	for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
> -		/*
> -		 * Get vertical and horizontal scanout position vpos, hpos,
> -		 * and bounding timestamps stime, etime, pre/post query.
> -		 */
> -		vbl_status = dev->driver->get_scanout_position(dev, pipe,
> -							       in_vblank_irq,
> -							       &vpos, &hpos,
> -							       &stime, &etime,
> -							       mode);
> -
> -		/* Return as no-op if scanout query unsupported or failed. */
> -		if (!vbl_status) {
> -			DRM_DEBUG("crtc %u : scanoutpos query failed.\n",
> -				  pipe);
> -			return false;
> -		}
> -
> -		/* Compute uncertainty in timestamp of scanout position query. */
> -		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
> -
> -		/* Accept result with <  max_error nsecs timing uncertainty. */
> -		if (duration_ns <= *max_error)
> -			break;
> -	}
> -
> -	/* Noisy system timing? */
> -	if (i == DRM_TIMESTAMP_MAXRETRIES) {
> -		DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n",
> -			  pipe, duration_ns/1000, *max_error/1000, i);
> -	}
> -
> -	/* Return upper bound of timestamp precision error. */
> -	*max_error = duration_ns;
> -
> -	/* Convert scanout position into elapsed time at raw_time query
> -	 * since start of scanout at first display scanline. delta_ns
> -	 * can be negative if start of scanout hasn't happened yet.
> -	 */
> -	delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
> -			   mode->crtc_clock);
> -
> -	if (!drm_timestamp_monotonic)
> -		etime = ktime_mono_to_real(etime);
> -
> -	/* save this only for debugging purposes */
> -	tv_etime = ktime_to_timeval(etime);
> -	/* Subtract time delta from raw timestamp to get final
> -	 * vblank_time timestamp for end of vblank.
> -	 */
> -	etime = ktime_sub_ns(etime, delta_ns);
> -	*vblank_time = ktime_to_timeval(etime);
> -
> -	DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
> -		      pipe, hpos, vpos,
> -		      (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
> -		      (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
> -		      duration_ns/1000, i);
> -
> -	return true;
> -}
> -EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
> -
> -static struct timeval get_drm_timestamp(void)
> -{
> -	ktime_t now;
> -
> -	now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
> -	return ktime_to_timeval(now);
> -}
> -
> -/**
> - * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
> - *                             vblank interval
> - * @dev: DRM device
> - * @pipe: index of CRTC whose vblank timestamp to retrieve
> - * @tvblank: Pointer to target struct timeval which should receive
> the timestamp
> - * @in_vblank_irq:
> - *     True when called from drm_crtc_handle_vblank().  Some drivers
> - *     need to apply some workarounds for gpu-specific vblank irq quirks
> - *     if flag is set.
> - *
> - * Fetches the system timestamp corresponding to the time of the most recent
> - * vblank interval on specified CRTC. May call into kms-driver to
> - * compute the timestamp with a high-precision GPU specific method.
> - *
> - * Returns zero if timestamp originates from uncorrected do_gettimeofday()
> - * call, i.e., it isn't very precisely locked to the true vblank.
> - *
> - * Returns:
> - * True if timestamp is considered to be very precise, false otherwise.
> - */
> -static bool
> -drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
> -			  struct timeval *tvblank, bool in_vblank_irq)
> -{
> -	bool ret = false;
> -
> -	/* Define requested maximum error on timestamps (nanoseconds). */
> -	int max_error = (int) drm_timestamp_precision * 1000;
> -
> -	/* Query driver if possible and precision timestamping enabled. */
> -	if (dev->driver->get_vblank_timestamp && (max_error > 0))
> -		ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error,
> -							tvblank, in_vblank_irq);
> -
> -	/* GPU high precision timestamp query unsupported or failed.
> -	 * Return current monotonic/gettimeofday timestamp as best estimate.
> -	 */
> -	if (!ret)
> -		*tvblank = get_drm_timestamp();
> -
> -	return ret;
> -}
> -
> -/**
> - * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
> - * @crtc: which counter to retrieve
> - *
> - * Fetches the "cooked" vblank count value that represents the number of
> - * vblank events since the system was booted, including lost events due to
> - * modesetting activity.
> - *
> - * Returns:
> - * The software vblank counter.
> - */
> -u32 drm_crtc_vblank_count(struct drm_crtc *crtc)
> -{
> -	return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
> -}
> -EXPORT_SYMBOL(drm_crtc_vblank_count);
> -
> -/**
> - * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the
> - *     system timestamp corresponding to that vblank counter value.
> - * @dev: DRM device
> - * @pipe: index of CRTC whose counter to retrieve
> - * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
> - *
> - * Fetches the "cooked" vblank count value that represents the number of
> - * vblank events since the system was booted, including lost events due to
> - * modesetting activity. Returns corresponding system timestamp of the time
> - * of the vblank interval that corresponds to the current vblank counter value.
> - *
> - * This is the legacy version of drm_crtc_vblank_count_and_time().
> - */
> -static u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
> -				     struct timeval *vblanktime)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	u32 vblank_count;
> -	unsigned int seq;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs)) {
> -		*vblanktime = (struct timeval) { 0 };
> -		return 0;
> -	}
> -
> -	do {
> -		seq = read_seqbegin(&vblank->seqlock);
> -		vblank_count = vblank->count;
> -		*vblanktime = vblank->time;
> -	} while (read_seqretry(&vblank->seqlock, seq));
> -
> -	return vblank_count;
> -}
> -
> -/**
> - * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
> - *     and the system timestamp corresponding to that vblank counter value
> - * @crtc: which counter to retrieve
> - * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
> - *
> - * Fetches the "cooked" vblank count value that represents the number of
> - * vblank events since the system was booted, including lost events due to
> - * modesetting activity. Returns corresponding system timestamp of the time
> - * of the vblank interval that corresponds to the current vblank counter value.
> - */
> -u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
> -				   struct timeval *vblanktime)
> -{
> -	return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
> -					 vblanktime);
> -}
> -EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
> -
> -static void send_vblank_event(struct drm_device *dev,
> -		struct drm_pending_vblank_event *e,
> -		unsigned long seq, struct timeval *now)
> -{
> -	e->event.sequence = seq;
> -	e->event.tv_sec = now->tv_sec;
> -	e->event.tv_usec = now->tv_usec;
> -
> -	trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe,
> -					 e->event.sequence);
> -
> -	drm_send_event_locked(dev, &e->base);
> -}
> -
> -/**
> - * drm_crtc_arm_vblank_event - arm vblank event after pageflip
> - * @crtc: the source CRTC of the vblank event
> - * @e: the event to send
> - *
> - * A lot of drivers need to generate vblank events for the very next vblank
> - * interrupt. For example when the page flip interrupt happens when the page
> - * flip gets armed, but not when it actually executes within the next vblank
> - * period. This helper function implements exactly the required vblank arming
> - * behaviour.
> - *
> - * NOTE: Drivers using this to send out the &drm_crtc_state.event as part of an
> - * atomic commit must ensure that the next vblank happens at exactly the same
> - * time as the atomic commit is committed to the hardware. This function itself
> - * does **not** protect again the next vblank interrupt racing with either this
> - * function call or the atomic commit operation. A possible sequence could be:
> - *
> - * 1. Driver commits new hardware state into vblank-synchronized registers.
> - * 2. A vblank happens, committing the hardware state. Also the corresponding
> - *    vblank interrupt is fired off and fully processed by the interrupt
> - *    handler.
> - * 3. The atomic commit operation proceeds to call drm_crtc_arm_vblank_event().
> - * 4. The event is only send out for the next vblank, which is wrong.
> - *
> - * An equivalent race can happen when the driver calls
> - * drm_crtc_arm_vblank_event() before writing out the new hardware state.
> - *
> - * The only way to make this work safely is to prevent the vblank from firing
> - * (and the hardware from committing anything else) until the entire atomic
> - * commit sequence has run to completion. If the hardware does not have such a
> - * feature (e.g. using a "go" bit), then it is unsafe to use this functions.
> - * Instead drivers need to manually send out the event from their interrupt
> - * handler by calling drm_crtc_send_vblank_event() and make sure that
> there's no
> - * possible race with the hardware committing the atomic update.
> - *
> - * Caller must hold event lock. Caller must also hold a vblank reference for
> - * the event @e, which will be dropped when the next vblank arrives.
> - */
> -void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
> -			       struct drm_pending_vblank_event *e)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	unsigned int pipe = drm_crtc_index(crtc);
> -
> -	assert_spin_locked(&dev->event_lock);
> -
> -	e->pipe = pipe;
> -	e->event.sequence = drm_vblank_count(dev, pipe);
> -	e->event.crtc_id = crtc->base.id;
> -	list_add_tail(&e->base.link, &dev->vblank_event_list);
> -}
> -EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
> -
> -/**
> - * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
> - * @crtc: the source CRTC of the vblank event
> - * @e: the event to send
> - *
> - * Updates sequence # and timestamp on event for the most recently processed
> - * vblank, and sends it to userspace.  Caller must hold event lock.
> - *
> - * See drm_crtc_arm_vblank_event() for a helper which can be used in certain
> - * situation, especially to send out events for atomic commit operations.
> - */
> -void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
> -				struct drm_pending_vblank_event *e)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	unsigned int seq, pipe = drm_crtc_index(crtc);
> -	struct timeval now;
> -
> -	if (dev->num_crtcs > 0) {
> -		seq = drm_vblank_count_and_time(dev, pipe, &now);
> -	} else {
> -		seq = 0;
> -
> -		now = get_drm_timestamp();
> -	}
> -	e->pipe = pipe;
> -	e->event.crtc_id = crtc->base.id;
> -	send_vblank_event(dev, e, seq, &now);
> -}
> -EXPORT_SYMBOL(drm_crtc_send_vblank_event);
> -
> -static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
> -{
> -	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> -		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> -
> -		if (crtc->funcs->enable_vblank)
> -			return crtc->funcs->enable_vblank(crtc);
> -	}
> -
> -	return dev->driver->enable_vblank(dev, pipe);
> -}
> -
> -/**
> - * drm_vblank_enable - enable the vblank interrupt on a CRTC
> - * @dev: DRM device
> - * @pipe: CRTC index
> - *
> - * Returns:
> - * Zero on success or a negative error code on failure.
> - */
> -static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	int ret = 0;
> -
> -	assert_spin_locked(&dev->vbl_lock);
> -
> -	spin_lock(&dev->vblank_time_lock);
> -
> -	if (!vblank->enabled) {
> -		/*
> -		 * Enable vblank irqs under vblank_time_lock protection.
> -		 * All vblank count & timestamp updates are held off
> -		 * until we are done reinitializing master counter and
> -		 * timestamps. Filtercode in drm_handle_vblank() will
> -		 * prevent double-accounting of same vblank interval.
> -		 */
> -		ret = __enable_vblank(dev, pipe);
> -		DRM_DEBUG("enabling vblank on crtc %u, ret: %d\n", pipe, ret);
> -		if (ret) {
> -			atomic_dec(&vblank->refcount);
> -		} else {
> -			drm_update_vblank_count(dev, pipe, 0);
> -			/* drm_update_vblank_count() includes a wmb so we just
> -			 * need to ensure that the compiler emits the write
> -			 * to mark the vblank as enabled after the call
> -			 * to drm_update_vblank_count().
> -			 */
> -			WRITE_ONCE(vblank->enabled, true);
> -		}
> -	}
> -
> -	spin_unlock(&dev->vblank_time_lock);
> -
> -	return ret;
> -}
> -
> -/**
> - * drm_vblank_get - get a reference count on vblank events
> - * @dev: DRM device
> - * @pipe: index of CRTC to own
> - *
> - * Acquire a reference count on vblank events to avoid having them disabled
> - * while in use.
> - *
> - * This is the legacy version of drm_crtc_vblank_get().
> - *
> - * Returns:
> - * Zero on success or a negative error code on failure.
> - */
> -static int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	unsigned long irqflags;
> -	int ret = 0;
> -
> -	if (!dev->num_crtcs)
> -		return -EINVAL;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return -EINVAL;
> -
> -	spin_lock_irqsave(&dev->vbl_lock, irqflags);
> -	/* Going from 0->1 means we have to enable interrupts again */
> -	if (atomic_add_return(1, &vblank->refcount) == 1) {
> -		ret = drm_vblank_enable(dev, pipe);
> -	} else {
> -		if (!vblank->enabled) {
> -			atomic_dec(&vblank->refcount);
> -			ret = -EINVAL;
> -		}
> -	}
> -	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> -
> -	return ret;
> -}
> -
> -/**
> - * drm_crtc_vblank_get - get a reference count on vblank events
> - * @crtc: which CRTC to own
> - *
> - * Acquire a reference count on vblank events to avoid having them disabled
> - * while in use.
> - *
> - * Returns:
> - * Zero on success or a negative error code on failure.
> - */
> -int drm_crtc_vblank_get(struct drm_crtc *crtc)
> -{
> -	return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
> -}
> -EXPORT_SYMBOL(drm_crtc_vblank_get);
> -
> -/**
> - * drm_vblank_put - release ownership of vblank events
> - * @dev: DRM device
> - * @pipe: index of CRTC to release
> - *
> - * Release ownership of a given vblank counter, turning off interrupts
> - * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
> - *
> - * This is the legacy version of drm_crtc_vblank_put().
> - */
> -static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return;
> -
> -	if (WARN_ON(atomic_read(&vblank->refcount) == 0))
> -		return;
> -
> -	/* Last user schedules interrupt disable */
> -	if (atomic_dec_and_test(&vblank->refcount)) {
> -		if (drm_vblank_offdelay == 0)
> -			return;
> -		else if (drm_vblank_offdelay < 0)
> -			vblank_disable_fn((unsigned long)vblank);
> -		else if (!dev->vblank_disable_immediate)
> -			mod_timer(&vblank->disable_timer,
> -				  jiffies + ((drm_vblank_offdelay * HZ)/1000));
> -	}
> -}
> -
> -/**
> - * drm_crtc_vblank_put - give up ownership of vblank events
> - * @crtc: which counter to give up
> - *
> - * Release ownership of a given vblank counter, turning off interrupts
> - * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
> - */
> -void drm_crtc_vblank_put(struct drm_crtc *crtc)
> -{
> -	drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
> -}
> -EXPORT_SYMBOL(drm_crtc_vblank_put);
> -
> -/**
> - * drm_wait_one_vblank - wait for one vblank
> - * @dev: DRM device
> - * @pipe: CRTC index
> - *
> - * This waits for one vblank to pass on @pipe, using the irq driver interfaces.
> - * It is a failure to call this when the vblank irq for @pipe is disabled, e.g.
> - * due to lack of driver support or because the crtc is off.
> - */
> -void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	int ret;
> -	u32 last;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return;
> -
> -	ret = drm_vblank_get(dev, pipe);
> -	if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", pipe, ret))
> -		return;
> -
> -	last = drm_vblank_count(dev, pipe);
> -
> -	ret = wait_event_timeout(vblank->queue,
> -				 last != drm_vblank_count(dev, pipe),
> -				 msecs_to_jiffies(100));
> -
> -	WARN(ret == 0, "vblank wait timed out on crtc %i\n", pipe);
> -
> -	drm_vblank_put(dev, pipe);
> -}
> -EXPORT_SYMBOL(drm_wait_one_vblank);
> -
> -/**
> - * drm_crtc_wait_one_vblank - wait for one vblank
> - * @crtc: DRM crtc
> - *
> - * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
> - * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
> - * due to lack of driver support or because the crtc is off.
> - */
> -void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
> -{
> -	drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
> -}
> -EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
> -
> -/**
> - * drm_crtc_vblank_off - disable vblank events on a CRTC
> - * @crtc: CRTC in question
> - *
> - * Drivers can use this function to shut down the vblank interrupt
> handling when
> - * disabling a crtc. This function ensures that the latest vblank
> frame count is
> - * stored so that drm_vblank_on can restore it again.
> - *
> - * Drivers must use this function when the hardware vblank counter can get
> - * reset, e.g. when suspending.
> - */
> -void drm_crtc_vblank_off(struct drm_crtc *crtc)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	unsigned int pipe = drm_crtc_index(crtc);
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	struct drm_pending_vblank_event *e, *t;
> -	struct timeval now;
> -	unsigned long irqflags;
> -	unsigned int seq;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return;
> -
> -	spin_lock_irqsave(&dev->event_lock, irqflags);
> -
> -	spin_lock(&dev->vbl_lock);
> -	DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
> -		      pipe, vblank->enabled, vblank->inmodeset);
> -
> -	/* Avoid redundant vblank disables without previous
> -	 * drm_crtc_vblank_on(). */
> -	if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
> -		vblank_disable_and_save(dev, pipe);
> -
> -	wake_up(&vblank->queue);
> -
> -	/*
> -	 * Prevent subsequent drm_vblank_get() from re-enabling
> -	 * the vblank interrupt by bumping the refcount.
> -	 */
> -	if (!vblank->inmodeset) {
> -		atomic_inc(&vblank->refcount);
> -		vblank->inmodeset = 1;
> -	}
> -	spin_unlock(&dev->vbl_lock);
> -
> -	/* Send any queued vblank events, lest the natives grow disquiet */
> -	seq = drm_vblank_count_and_time(dev, pipe, &now);
> -
> -	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
> -		if (e->pipe != pipe)
> -			continue;
> -		DRM_DEBUG("Sending premature vblank event on disable: "
> -			  "wanted %u, current %u\n",
> -			  e->event.sequence, seq);
> -		list_del(&e->base.link);
> -		drm_vblank_put(dev, pipe);
> -		send_vblank_event(dev, e, seq, &now);
> -	}
> -	spin_unlock_irqrestore(&dev->event_lock, irqflags);
> -
> -	/* Will be reset by the modeset helpers when re-enabling the crtc by
> -	 * calling drm_calc_timestamping_constants(). */
> -	vblank->hwmode.crtc_clock = 0;
> -}
> -EXPORT_SYMBOL(drm_crtc_vblank_off);
> -
> -/**
> - * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
> - * @crtc: CRTC in question
> - *
> - * Drivers can use this function to reset the vblank state to off at load time.
> - * Drivers should use this together with the drm_crtc_vblank_off() and
> - * drm_crtc_vblank_on() functions. The difference compared to
> - * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
> - * and hence doesn't need to call any driver hooks.
> - */
> -void drm_crtc_vblank_reset(struct drm_crtc *crtc)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	unsigned long irqflags;
> -	unsigned int pipe = drm_crtc_index(crtc);
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -
> -	spin_lock_irqsave(&dev->vbl_lock, irqflags);
> -	/*
> -	 * Prevent subsequent drm_vblank_get() from enabling the vblank
> -	 * interrupt by bumping the refcount.
> -	 */
> -	if (!vblank->inmodeset) {
> -		atomic_inc(&vblank->refcount);
> -		vblank->inmodeset = 1;
> -	}
> -	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> -
> -	WARN_ON(!list_empty(&dev->vblank_event_list));
> -}
> -EXPORT_SYMBOL(drm_crtc_vblank_reset);
> -
> -/**
> - * drm_crtc_vblank_on - enable vblank events on a CRTC
> - * @crtc: CRTC in question
> - *
> - * This functions restores the vblank interrupt state captured with
> - * drm_crtc_vblank_off() again. Note that calls to drm_crtc_vblank_on() and
> - * drm_crtc_vblank_off() can be unbalanced and so can also be
> unconditionally called
> - * in driver load code to reflect the current hardware state of the crtc.
> - */
> -void drm_crtc_vblank_on(struct drm_crtc *crtc)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	unsigned int pipe = drm_crtc_index(crtc);
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	unsigned long irqflags;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return;
> -
> -	spin_lock_irqsave(&dev->vbl_lock, irqflags);
> -	DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
> -		      pipe, vblank->enabled, vblank->inmodeset);
> -
> -	/* Drop our private "prevent drm_vblank_get" refcount */
> -	if (vblank->inmodeset) {
> -		atomic_dec(&vblank->refcount);
> -		vblank->inmodeset = 0;
> -	}
> -
> -	drm_reset_vblank_timestamp(dev, pipe);
> -
> -	/*
> -	 * re-enable interrupts if there are users left, or the
> -	 * user wishes vblank interrupts to be enabled all the time.
> -	 */
> -	if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0)
> -		WARN_ON(drm_vblank_enable(dev, pipe));
> -	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> -}
> -EXPORT_SYMBOL(drm_crtc_vblank_on);
> -
> -static void drm_legacy_vblank_pre_modeset(struct drm_device *dev,
> -					  unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -
> -	/* vblank is not initialized (IRQ not installed ?), or has been freed */
> -	if (!dev->num_crtcs)
> -		return;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return;
> -
> -	/*
> -	 * To avoid all the problems that might happen if interrupts
> -	 * were enabled/disabled around or between these calls, we just
> -	 * have the kernel take a reference on the CRTC (just once though
> -	 * to avoid corrupting the count if multiple, mismatch calls occur),
> -	 * so that interrupts remain enabled in the interim.
> -	 */
> -	if (!vblank->inmodeset) {
> -		vblank->inmodeset = 0x1;
> -		if (drm_vblank_get(dev, pipe) == 0)
> -			vblank->inmodeset |= 0x2;
> -	}
> -}
> -
> -static void drm_legacy_vblank_post_modeset(struct drm_device *dev,
> -					   unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	unsigned long irqflags;
> -
> -	/* vblank is not initialized (IRQ not installed ?), or has been freed */
> -	if (!dev->num_crtcs)
> -		return;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return;
> -
> -	if (vblank->inmodeset) {
> -		spin_lock_irqsave(&dev->vbl_lock, irqflags);
> -		drm_reset_vblank_timestamp(dev, pipe);
> -		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> -
> -		if (vblank->inmodeset & 0x2)
> -			drm_vblank_put(dev, pipe);
> -
> -		vblank->inmodeset = 0;
> -	}
> -}
> -
> -int drm_legacy_modeset_ctl(struct drm_device *dev, void *data,
> -			   struct drm_file *file_priv)
> -{
> -	struct drm_modeset_ctl *modeset = data;
> -	unsigned int pipe;
> -
> -	/* If drm_vblank_init() hasn't been called yet, just no-op */
> -	if (!dev->num_crtcs)
> -		return 0;
> -
> -	/* KMS drivers handle this internally */
> -	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
> -		return 0;
> -
> -	pipe = modeset->crtc;
> -	if (pipe >= dev->num_crtcs)
> -		return -EINVAL;
> -
> -	switch (modeset->cmd) {
> -	case _DRM_PRE_MODESET:
> -		drm_legacy_vblank_pre_modeset(dev, pipe);
> -		break;
> -	case _DRM_POST_MODESET:
> -		drm_legacy_vblank_post_modeset(dev, pipe);
> -		break;
> -	default:
> -		return -EINVAL;
> -	}
> -
> -	return 0;
> -}
> -
> -static inline bool vblank_passed(u32 seq, u32 ref)
> -{
> -	return (seq - ref) <= (1 << 23);
> -}
> -
> -static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
> -				  union drm_wait_vblank *vblwait,
> -				  struct drm_file *file_priv)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	struct drm_pending_vblank_event *e;
> -	struct timeval now;
> -	unsigned long flags;
> -	unsigned int seq;
> -	int ret;
> -
> -	e = kzalloc(sizeof(*e), GFP_KERNEL);
> -	if (e == NULL) {
> -		ret = -ENOMEM;
> -		goto err_put;
> -	}
> -
> -	e->pipe = pipe;
> -	e->event.base.type = DRM_EVENT_VBLANK;
> -	e->event.base.length = sizeof(e->event);
> -	e->event.user_data = vblwait->request.signal;
> -
> -	spin_lock_irqsave(&dev->event_lock, flags);
> -
> -	/*
> -	 * drm_crtc_vblank_off() might have been called after we called
> -	 * drm_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
> -	 * vblank disable, so no need for further locking.  The reference from
> -	 * drm_vblank_get() protects against vblank disable from another source.
> -	 */
> -	if (!READ_ONCE(vblank->enabled)) {
> -		ret = -EINVAL;
> -		goto err_unlock;
> -	}
> -
> -	ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
> -					    &e->event.base);
> -
> -	if (ret)
> -		goto err_unlock;
> -
> -	seq = drm_vblank_count_and_time(dev, pipe, &now);
> -
> -	DRM_DEBUG("event on vblank count %u, current %u, crtc %u\n",
> -		  vblwait->request.sequence, seq, pipe);
> -
> -	trace_drm_vblank_event_queued(file_priv, pipe,
> -				      vblwait->request.sequence);
> -
> -	e->event.sequence = vblwait->request.sequence;
> -	if (vblank_passed(seq, vblwait->request.sequence)) {
> -		drm_vblank_put(dev, pipe);
> -		send_vblank_event(dev, e, seq, &now);
> -		vblwait->reply.sequence = seq;
> -	} else {
> -		/* drm_handle_vblank_events will call drm_vblank_put */
> -		list_add_tail(&e->base.link, &dev->vblank_event_list);
> -		vblwait->reply.sequence = vblwait->request.sequence;
> -	}
> -
> -	spin_unlock_irqrestore(&dev->event_lock, flags);
> -
> -	return 0;
> -
> -err_unlock:
> -	spin_unlock_irqrestore(&dev->event_lock, flags);
> -	kfree(e);
> -err_put:
> -	drm_vblank_put(dev, pipe);
> -	return ret;
> -}
> -
> -static bool drm_wait_vblank_is_query(union drm_wait_vblank *vblwait)
> -{
> -	if (vblwait->request.sequence)
> -		return false;
> -
> -	return _DRM_VBLANK_RELATIVE ==
> -		(vblwait->request.type & (_DRM_VBLANK_TYPES_MASK |
> -					  _DRM_VBLANK_EVENT |
> -					  _DRM_VBLANK_NEXTONMISS));
> -}
> -
> -/*
> - * Wait for VBLANK.
> - *
> - * \param inode device inode.
> - * \param file_priv DRM file private.
> - * \param cmd command.
> - * \param data user argument, pointing to a drm_wait_vblank structure.
> - * \return zero on success or a negative number on failure.
> - *
> - * This function enables the vblank interrupt on the pipe requested, then
> - * sleeps waiting for the requested sequence number to occur, and drops
> - * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
> - * after a timeout with no further vblank waits scheduled).
> - */
> -int drm_wait_vblank(struct drm_device *dev, void *data,
> -		    struct drm_file *file_priv)
> -{
> -	struct drm_vblank_crtc *vblank;
> -	union drm_wait_vblank *vblwait = data;
> -	int ret;
> -	unsigned int flags, seq, pipe, high_pipe;
> -
> -	if (!dev->irq_enabled)
> -		return -EINVAL;
> -
> -	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
> -		return -EINVAL;
> -
> -	if (vblwait->request.type &
> -	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
> -	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
> -		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
> -			  vblwait->request.type,
> -			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
> -			   _DRM_VBLANK_HIGH_CRTC_MASK));
> -		return -EINVAL;
> -	}
> -
> -	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
> -	high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
> -	if (high_pipe)
> -		pipe = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
> -	else
> -		pipe = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
> -	if (pipe >= dev->num_crtcs)
> -		return -EINVAL;
> -
> -	vblank = &dev->vblank[pipe];
> -
> -	/* If the counter is currently enabled and accurate, short-circuit
> -	 * queries to return the cached timestamp of the last vblank.
> -	 */
> -	if (dev->vblank_disable_immediate &&
> -	    drm_wait_vblank_is_query(vblwait) &&
> -	    READ_ONCE(vblank->enabled)) {
> -		struct timeval now;
> -
> -		vblwait->reply.sequence =
> -			drm_vblank_count_and_time(dev, pipe, &now);
> -		vblwait->reply.tval_sec = now.tv_sec;
> -		vblwait->reply.tval_usec = now.tv_usec;
> -		return 0;
> -	}
> -
> -	ret = drm_vblank_get(dev, pipe);
> -	if (ret) {
> -		DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
> -		return ret;
> -	}
> -	seq = drm_vblank_count(dev, pipe);
> -
> -	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
> -	case _DRM_VBLANK_RELATIVE:
> -		vblwait->request.sequence += seq;
> -		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
> -	case _DRM_VBLANK_ABSOLUTE:
> -		break;
> -	default:
> -		ret = -EINVAL;
> -		goto done;
> -	}
> -
> -	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
> -	    vblank_passed(seq, vblwait->request.sequence))
> -		vblwait->request.sequence = seq + 1;
> -
> -	if (flags & _DRM_VBLANK_EVENT) {
> -		/* must hold on to the vblank ref until the event fires
> -		 * drm_vblank_put will be called asynchronously
> -		 */
> -		return drm_queue_vblank_event(dev, pipe, vblwait, file_priv);
> -	}
> -
> -	if (vblwait->request.sequence != seq) {
> -		DRM_DEBUG("waiting on vblank count %u, crtc %u\n",
> -			  vblwait->request.sequence, pipe);
> -		DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
> -			    vblank_passed(drm_vblank_count(dev, pipe),
> -					  vblwait->request.sequence) ||
> -			    !READ_ONCE(vblank->enabled));
> -	}
> -
> -	if (ret != -EINTR) {
> -		struct timeval now;
> -
> -		vblwait->reply.sequence = drm_vblank_count_and_time(dev, pipe, &now);
> -		vblwait->reply.tval_sec = now.tv_sec;
> -		vblwait->reply.tval_usec = now.tv_usec;
> -
> -		DRM_DEBUG("crtc %d returning %u to client\n",
> -			  pipe, vblwait->reply.sequence);
> -	} else {
> -		DRM_DEBUG("crtc %d vblank wait interrupted by signal\n", pipe);
> -	}
> -
> -done:
> -	drm_vblank_put(dev, pipe);
> -	return ret;
> -}
> -
> -static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
> -{
> -	struct drm_pending_vblank_event *e, *t;
> -	struct timeval now;
> -	unsigned int seq;
> -
> -	assert_spin_locked(&dev->event_lock);
> -
> -	seq = drm_vblank_count_and_time(dev, pipe, &now);
> -
> -	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
> -		if (e->pipe != pipe)
> -			continue;
> -		if (!vblank_passed(seq, e->event.sequence))
> -			continue;
> -
> -		DRM_DEBUG("vblank event on %u, current %u\n",
> -			  e->event.sequence, seq);
> -
> -		list_del(&e->base.link);
> -		drm_vblank_put(dev, pipe);
> -		send_vblank_event(dev, e, seq, &now);
> -	}
> -
> -	trace_drm_vblank_event(pipe, seq);
> -}
> -
> -/**
> - * drm_handle_vblank - handle a vblank event
> - * @dev: DRM device
> - * @pipe: index of CRTC where this event occurred
> - *
> - * Drivers should call this routine in their vblank interrupt handlers to
> - * update the vblank counter and send any signals that may be pending.
> - *
> - * This is the legacy version of drm_crtc_handle_vblank().
> - */
> -bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
> -{
> -	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -	unsigned long irqflags;
> -	bool disable_irq;
> -
> -	if (WARN_ON_ONCE(!dev->num_crtcs))
> -		return false;
> -
> -	if (WARN_ON(pipe >= dev->num_crtcs))
> -		return false;
> -
> -	spin_lock_irqsave(&dev->event_lock, irqflags);
> -
> -	/* Need timestamp lock to prevent concurrent execution with
> -	 * vblank enable/disable, as this would cause inconsistent
> -	 * or corrupted timestamps and vblank counts.
> -	 */
> -	spin_lock(&dev->vblank_time_lock);
> -
> -	/* Vblank irq handling disabled. Nothing to do. */
> -	if (!vblank->enabled) {
> -		spin_unlock(&dev->vblank_time_lock);
> -		spin_unlock_irqrestore(&dev->event_lock, irqflags);
> -		return false;
> -	}
> -
> -	drm_update_vblank_count(dev, pipe, true);
> -
> -	spin_unlock(&dev->vblank_time_lock);
> -
> -	wake_up(&vblank->queue);
> -
> -	/* With instant-off, we defer disabling the interrupt until after
> -	 * we finish processing the following vblank after all events have
> -	 * been signaled. The disable has to be last (after
> -	 * drm_handle_vblank_events) so that the timestamp is always accurate.
> -	 */
> -	disable_irq = (dev->vblank_disable_immediate &&
> -		       drm_vblank_offdelay > 0 &&
> -		       !atomic_read(&vblank->refcount));
> -
> -	drm_handle_vblank_events(dev, pipe);
> -
> -	spin_unlock_irqrestore(&dev->event_lock, irqflags);
> -
> -	if (disable_irq)
> -		vblank_disable_fn((unsigned long)vblank);
> -
> -	return true;
> -}
> -EXPORT_SYMBOL(drm_handle_vblank);
> -
> -/**
> - * drm_crtc_handle_vblank - handle a vblank event
> - * @crtc: where this event occurred
> - *
> - * Drivers should call this routine in their vblank interrupt handlers to
> - * update the vblank counter and send any signals that may be pending.
> - *
> - * This is the native KMS version of drm_handle_vblank().
> - *
> - * Returns:
> - * True if the event was successfully handled, false on failure.
> - */
> -bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
> -{
> -	return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
> -}
> -EXPORT_SYMBOL(drm_crtc_handle_vblank);
> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> new file mode 100644
> index 000000000000..630dc26379b7
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_vblank.c
> @@ -0,0 +1,1645 @@
> +/*
> + * drm_irq.c IRQ and vblank support
> + *
> + * \author Rickard E. (Rik) Faith <faith at valinux.com>
> + * \author Gareth Hughes <gareth at valinux.com>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + */
> +
> +#include <drm/drm_vblank.h>
> +#include <drm/drmP.h>
> +#include <linux/export.h>
> +
> +#include "drm_trace.h"
> +#include "drm_internal.h"
> +
> +/* Retry timestamp calculation up to 3 times to satisfy
> + * drm_timestamp_precision before giving up.
> + */
> +#define DRM_TIMESTAMP_MAXRETRIES 3
> +
> +/* Threshold in nanoseconds for detection of redundant
> + * vblank irq in drm_handle_vblank(). 1 msec should be ok.
> + */
> +#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
> +
> +static bool
> +drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
> +			  struct timeval *tvblank, bool in_vblank_irq);
> +
> +static unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */
> +
> +/*
> + * Default to use monotonic timestamps for wait-for-vblank and page-flip
> + * complete events.
> + */
> +unsigned int drm_timestamp_monotonic = 1;
> +
> +static int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */
> +
> +module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
> +module_param_named(timestamp_precision_usec, drm_timestamp_precision,
> int, 0600);
> +module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
> +MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable
> [msecs] (0: never disable, <0: disable immediately)");
> +MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
> +MODULE_PARM_DESC(timestamp_monotonic, "Use monotonic timestamps");
> +
> +static void store_vblank(struct drm_device *dev, unsigned int pipe,
> +			 u32 vblank_count_inc,
> +			 struct timeval *t_vblank, u32 last)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +
> +	assert_spin_locked(&dev->vblank_time_lock);
> +
> +	vblank->last = last;
> +
> +	write_seqlock(&vblank->seqlock);
> +	vblank->time = *t_vblank;
> +	vblank->count += vblank_count_inc;
> +	write_sequnlock(&vblank->seqlock);
> +}
> +
> +/*
> + * "No hw counter" fallback implementation of .get_vblank_counter() hook,
> + * if there is no useable hardware frame counter available.
> + */
> +static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
> +{
> +	WARN_ON_ONCE(dev->max_vblank_count != 0);
> +	return 0;
> +}
> +
> +static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
> +{
> +	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> +		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> +
> +		if (crtc->funcs->get_vblank_counter)
> +			return crtc->funcs->get_vblank_counter(crtc);
> +	}
> +
> +	if (dev->driver->get_vblank_counter)
> +		return dev->driver->get_vblank_counter(dev, pipe);
> +
> +	return drm_vblank_no_hw_counter(dev, pipe);
> +}
> +
> +/*
> + * Reset the stored timestamp for the current vblank count to correspond
> + * to the last vblank occurred.
> + *
> + * Only to be called from drm_crtc_vblank_on().
> + *
> + * Note: caller must hold &drm_device.vbl_lock since this reads & writes
> + * device vblank fields.
> + */
> +static void drm_reset_vblank_timestamp(struct drm_device *dev,
> unsigned int pipe)
> +{
> +	u32 cur_vblank;
> +	bool rc;
> +	struct timeval t_vblank;
> +	int count = DRM_TIMESTAMP_MAXRETRIES;
> +
> +	spin_lock(&dev->vblank_time_lock);
> +
> +	/*
> +	 * sample the current counter to avoid random jumps
> +	 * when drm_vblank_enable() applies the diff
> +	 */
> +	do {
> +		cur_vblank = __get_vblank_counter(dev, pipe);
> +		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
> +	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
> +
> +	/*
> +	 * Only reinitialize corresponding vblank timestamp if high-precision query
> +	 * available and didn't fail. Otherwise reinitialize delayed at next vblank
> +	 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
> +	 */
> +	if (!rc)
> +		t_vblank = (struct timeval) {0, 0};
> +
> +	/*
> +	 * +1 to make sure user will never see the same
> +	 * vblank counter value before and after a modeset
> +	 */
> +	store_vblank(dev, pipe, 1, &t_vblank, cur_vblank);
> +
> +	spin_unlock(&dev->vblank_time_lock);
> +}
> +
> +/*
> + * Call back into the driver to update the appropriate vblank counter
> + * (specified by @pipe).  Deal with wraparound, if it occurred, and
> + * update the last read value so we can deal with wraparound on the next
> + * call if necessary.
> + *
> + * Only necessary when going from off->on, to account for frames we
> + * didn't get an interrupt for.
> + *
> + * Note: caller must hold &drm_device.vbl_lock since this reads & writes
> + * device vblank fields.
> + */
> +static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
> +				    bool in_vblank_irq)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	u32 cur_vblank, diff;
> +	bool rc;
> +	struct timeval t_vblank;
> +	int count = DRM_TIMESTAMP_MAXRETRIES;
> +	int framedur_ns = vblank->framedur_ns;
> +
> +	/*
> +	 * Interrupts were disabled prior to this call, so deal with counter
> +	 * wrap if needed.
> +	 * NOTE!  It's possible we lost a full dev->max_vblank_count + 1 events
> +	 * here if the register is small or we had vblank interrupts off for
> +	 * a long time.
> +	 *
> +	 * We repeat the hardware vblank counter & timestamp query until
> +	 * we get consistent results. This to prevent races between gpu
> +	 * updating its hardware counter while we are retrieving the
> +	 * corresponding vblank timestamp.
> +	 */
> +	do {
> +		cur_vblank = __get_vblank_counter(dev, pipe);
> +		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq);
> +	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
> +
> +	if (dev->max_vblank_count != 0) {
> +		/* trust the hw counter when it's around */
> +		diff = (cur_vblank - vblank->last) & dev->max_vblank_count;
> +	} else if (rc && framedur_ns) {
> +		const struct timeval *t_old;
> +		u64 diff_ns;
> +
> +		t_old = &vblank->time;
> +		diff_ns = timeval_to_ns(&t_vblank) - timeval_to_ns(t_old);
> +
> +		/*
> +		 * Figure out how many vblanks we've missed based
> +		 * on the difference in the timestamps and the
> +		 * frame/field duration.
> +		 */
> +		diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
> +
> +		if (diff == 0 && in_vblank_irq)
> +			DRM_DEBUG_VBL("crtc %u: Redundant vblirq ignored."
> +				      " diff_ns = %lld, framedur_ns = %d)\n",
> +				      pipe, (long long) diff_ns, framedur_ns);
> +	} else {
> +		/* some kind of default for drivers w/o accurate vbl timestamping */
> +		diff = in_vblank_irq ? 1 : 0;
> +	}
> +
> +	/*
> +	 * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
> +	 * interval? If so then vblank irqs keep running and it will likely
> +	 * happen that the hardware vblank counter is not trustworthy as it
> +	 * might reset at some point in that interval and vblank timestamps
> +	 * are not trustworthy either in that interval. Iow. this can result
> +	 * in a bogus diff >> 1 which must be avoided as it would cause
> +	 * random large forward jumps of the software vblank counter.
> +	 */
> +	if (diff > 1 && (vblank->inmodeset & 0x2)) {
> +		DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u"
> +			      " due to pre-modeset.\n", pipe, diff);
> +		diff = 1;
> +	}
> +
> +	DRM_DEBUG_VBL("updating vblank count on crtc %u:"
> +		      " current=%u, diff=%u, hw=%u hw_last=%u\n",
> +		      pipe, vblank->count, diff, cur_vblank, vblank->last);
> +
> +	if (diff == 0) {
> +		WARN_ON_ONCE(cur_vblank != vblank->last);
> +		return;
> +	}
> +
> +	/*
> +	 * Only reinitialize corresponding vblank timestamp if high-precision query
> +	 * available and didn't fail, or we were called from the vblank interrupt.
> +	 * Otherwise reinitialize delayed at next vblank interrupt and assign 0
> +	 * for now, to mark the vblanktimestamp as invalid.
> +	 */
> +	if (!rc && in_vblank_irq)
> +		t_vblank = (struct timeval) {0, 0};
> +
> +	store_vblank(dev, pipe, diff, &t_vblank, cur_vblank);
> +}
> +
> +static u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return 0;
> +
> +	return vblank->count;
> +}
> +
> +/**
> + * drm_accurate_vblank_count - retrieve the master vblank counter
> + * @crtc: which counter to retrieve
> + *
> + * This function is similar to @drm_crtc_vblank_count but this
> + * function interpolates to handle a race with vblank irq's.
> + *
> + * This is mostly useful for hardware that can obtain the scanout
> + * position, but doesn't have a frame counter.
> + */
> +u32 drm_accurate_vblank_count(struct drm_crtc *crtc)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	unsigned int pipe = drm_crtc_index(crtc);
> +	u32 vblank;
> +	unsigned long flags;
> +
> +	WARN(!dev->driver->get_vblank_timestamp,
> +	     "This function requires support for accurate vblank timestamps.");
> +
> +	spin_lock_irqsave(&dev->vblank_time_lock, flags);
> +
> +	drm_update_vblank_count(dev, pipe, false);
> +	vblank = drm_vblank_count(dev, pipe);
> +
> +	spin_unlock_irqrestore(&dev->vblank_time_lock, flags);
> +
> +	return vblank;
> +}
> +EXPORT_SYMBOL(drm_accurate_vblank_count);
> +
> +static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
> +{
> +	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> +		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> +
> +		if (crtc->funcs->disable_vblank) {
> +			crtc->funcs->disable_vblank(crtc);
> +			return;
> +		}
> +	}
> +
> +	dev->driver->disable_vblank(dev, pipe);
> +}
> +
> +/*
> + * Disable vblank irq's on crtc, make sure that last vblank count
> + * of hardware and corresponding consistent software vblank counter
> + * are preserved, even if there are any spurious vblank irq's after
> + * disable.
> + */
> +void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	unsigned long irqflags;
> +
> +	assert_spin_locked(&dev->vbl_lock);
> +
> +	/* Prevent vblank irq processing while disabling vblank irqs,
> +	 * so no updates of timestamps or count can happen after we've
> +	 * disabled. Needed to prevent races in case of delayed irq's.
> +	 */
> +	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
> +
> +	/*
> +	 * Only disable vblank interrupts if they're enabled. This avoids
> +	 * calling the ->disable_vblank() operation in atomic context with the
> +	 * hardware potentially runtime suspended.
> +	 */
> +	if (vblank->enabled) {
> +		__disable_vblank(dev, pipe);
> +		vblank->enabled = false;
> +	}
> +
> +	/*
> +	 * Always update the count and timestamp to maintain the
> +	 * appearance that the counter has been ticking all along until
> +	 * this time. This makes the count account for the entire time
> +	 * between drm_crtc_vblank_on() and drm_crtc_vblank_off().
> +	 */
> +	drm_update_vblank_count(dev, pipe, false);
> +
> +	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
> +}
> +
> +static void vblank_disable_fn(unsigned long arg)
> +{
> +	struct drm_vblank_crtc *vblank = (void *)arg;
> +	struct drm_device *dev = vblank->dev;
> +	unsigned int pipe = vblank->pipe;
> +	unsigned long irqflags;
> +
> +	spin_lock_irqsave(&dev->vbl_lock, irqflags);
> +	if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
> +		DRM_DEBUG("disabling vblank on crtc %u\n", pipe);
> +		drm_vblank_disable_and_save(dev, pipe);
> +	}
> +	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> +}
> +
> +/**
> + * drm_vblank_cleanup - cleanup vblank support
> + * @dev: DRM device
> + *
> + * This function cleans up any resources allocated in drm_vblank_init.
> + */
> +void drm_vblank_cleanup(struct drm_device *dev)
> +{
> +	unsigned int pipe;
> +
> +	/* Bail if the driver didn't call drm_vblank_init() */
> +	if (dev->num_crtcs == 0)
> +		return;
> +
> +	for (pipe = 0; pipe < dev->num_crtcs; pipe++) {
> +		struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +
> +		WARN_ON(READ_ONCE(vblank->enabled) &&
> +			drm_core_check_feature(dev, DRIVER_MODESET));
> +
> +		del_timer_sync(&vblank->disable_timer);
> +	}
> +
> +	kfree(dev->vblank);
> +
> +	dev->num_crtcs = 0;
> +}
> +EXPORT_SYMBOL(drm_vblank_cleanup);
> +
> +/**
> + * drm_vblank_init - initialize vblank support
> + * @dev: DRM device
> + * @num_crtcs: number of CRTCs supported by @dev
> + *
> + * This function initializes vblank support for @num_crtcs display pipelines.
> + *
> + * Returns:
> + * Zero on success or a negative error code on failure.
> + */
> +int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
> +{
> +	int ret = -ENOMEM;
> +	unsigned int i;
> +
> +	spin_lock_init(&dev->vbl_lock);
> +	spin_lock_init(&dev->vblank_time_lock);
> +
> +	dev->num_crtcs = num_crtcs;
> +
> +	dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
> +	if (!dev->vblank)
> +		goto err;
> +
> +	for (i = 0; i < num_crtcs; i++) {
> +		struct drm_vblank_crtc *vblank = &dev->vblank[i];
> +
> +		vblank->dev = dev;
> +		vblank->pipe = i;
> +		init_waitqueue_head(&vblank->queue);
> +		setup_timer(&vblank->disable_timer, vblank_disable_fn,
> +			    (unsigned long)vblank);
> +		seqlock_init(&vblank->seqlock);
> +	}
> +
> +	DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
> +
> +	/* Driver specific high-precision vblank timestamping supported? */
> +	if (dev->driver->get_vblank_timestamp)
> +		DRM_INFO("Driver supports precise vblank timestamp query.\n");
> +	else
> +		DRM_INFO("No driver support for vblank timestamp query.\n");
> +
> +	/* Must have precise timestamping for reliable vblank instant disable */
> +	if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
> +		dev->vblank_disable_immediate = false;
> +		DRM_INFO("Setting vblank_disable_immediate to false because "
> +			 "get_vblank_timestamp == NULL\n");
> +	}
> +
> +	return 0;
> +
> +err:
> +	dev->num_crtcs = 0;
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_vblank_init);
> +
> +/**
> + * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
> + * @crtc: which CRTC's vblank waitqueue to retrieve
> + *
> + * This function returns a pointer to the vblank waitqueue for the CRTC.
> + * Drivers can use this to implement vblank waits using wait_event()
> and related
> + * functions.
> + */
> +wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc)
> +{
> +	return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
> +}
> +EXPORT_SYMBOL(drm_crtc_vblank_waitqueue);
> +
> +
> +/**
> + * drm_calc_timestamping_constants - calculate vblank timestamp constants
> + * @crtc: drm_crtc whose timestamp constants should be updated.
> + * @mode: display mode containing the scanout timings
> + *
> + * Calculate and store various constants which are later
> + * needed by vblank and swap-completion timestamping, e.g,
> + * by drm_calc_vbltimestamp_from_scanoutpos(). They are
> + * derived from CRTC's true scanout timing, so they take
> + * things like panel scaling or other adjustments into account.
> + */
> +void drm_calc_timestamping_constants(struct drm_crtc *crtc,
> +				     const struct drm_display_mode *mode)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	unsigned int pipe = drm_crtc_index(crtc);
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	int linedur_ns = 0, framedur_ns = 0;
> +	int dotclock = mode->crtc_clock;
> +
> +	if (!dev->num_crtcs)
> +		return;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return;
> +
> +	/* Valid dotclock? */
> +	if (dotclock > 0) {
> +		int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
> +
> +		/*
> +		 * Convert scanline length in pixels and video
> +		 * dot clock to line duration and frame duration
> +		 * in nanoseconds:
> +		 */
> +		linedur_ns  = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
> +		framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
> +
> +		/*
> +		 * Fields of interlaced scanout modes are only half a frame duration.
> +		 */
> +		if (mode->flags & DRM_MODE_FLAG_INTERLACE)
> +			framedur_ns /= 2;
> +	} else
> +		DRM_ERROR("crtc %u: Can't calculate constants, dotclock = 0!\n",
> +			  crtc->base.id);
> +
> +	vblank->linedur_ns  = linedur_ns;
> +	vblank->framedur_ns = framedur_ns;
> +	vblank->hwmode = *mode;
> +
> +	DRM_DEBUG("crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
> +		  crtc->base.id, mode->crtc_htotal,
> +		  mode->crtc_vtotal, mode->crtc_vdisplay);
> +	DRM_DEBUG("crtc %u: clock %d kHz framedur %d linedur %d\n",
> +		  crtc->base.id, dotclock, framedur_ns, linedur_ns);
> +}
> +EXPORT_SYMBOL(drm_calc_timestamping_constants);
> +
> +/**
> + * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
> + * @dev: DRM device
> + * @pipe: index of CRTC whose vblank timestamp to retrieve
> + * @max_error: Desired maximum allowable error in timestamps (nanosecs)
> + *             On return contains true maximum error of timestamp
> + * @vblank_time: Pointer to struct timeval which should receive the timestamp
> + * @in_vblank_irq:
> + *     True when called from drm_crtc_handle_vblank().  Some drivers
> + *     need to apply some workarounds for gpu-specific vblank irq quirks
> + *     if flag is set.
> + *
> + * Implements calculation of exact vblank timestamps from given
> drm_display_mode
> + * timings and current video scanout position of a CRTC. This can be
> called from
> + * within get_vblank_timestamp() implementation of a kms driver to
> implement the
> + * actual timestamping.
> + *
> + * Should return timestamps conforming to the OML_sync_control OpenML
> + * extension specification. The timestamp corresponds to the end of
> + * the vblank interval, aka start of scanout of topmost-leftmost display
> + * pixel in the following video frame.
> + *
> + * Requires support for optional dev->driver->get_scanout_position()
> + * in kms driver, plus a bit of setup code to provide a drm_display_mode
> + * that corresponds to the true scanout timing.
> + *
> + * The current implementation only handles standard video modes. It
> + * returns as no operation if a doublescan or interlaced video mode is
> + * active. Higher level code is expected to handle this.
> + *
> + * This function can be used to implement the &drm_driver.get_vblank_timestamp
> + * directly, if the driver implements the
> &drm_driver.get_scanout_position hook.
> + *
> + * Note that atomic drivers must call drm_calc_timestamping_constants() before
> + * enabling a CRTC. The atomic helpers already take care of that in
> + * drm_atomic_helper_update_legacy_modeset_state().
> + *
> + * Returns:
> + *
> + * Returns true on success, and false on failure, i.e. when no accurate
> + * timestamp could be acquired.
> + */
> +bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
> +					   unsigned int pipe,
> +					   int *max_error,
> +					   struct timeval *vblank_time,
> +					   bool in_vblank_irq)
> +{
> +	struct timeval tv_etime;
> +	ktime_t stime, etime;
> +	bool vbl_status;
> +	struct drm_crtc *crtc;
> +	const struct drm_display_mode *mode;
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	int vpos, hpos, i;
> +	int delta_ns, duration_ns;
> +
> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> +		return false;
> +
> +	crtc = drm_crtc_from_index(dev, pipe);
> +
> +	if (pipe >= dev->num_crtcs || !crtc) {
> +		DRM_ERROR("Invalid crtc %u\n", pipe);
> +		return false;
> +	}
> +
> +	/* Scanout position query not supported? Should not happen. */
> +	if (!dev->driver->get_scanout_position) {
> +		DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
> +		return false;
> +	}
> +
> +	if (drm_drv_uses_atomic_modeset(dev))
> +		mode = &vblank->hwmode;
> +	else
> +		mode = &crtc->hwmode;
> +
> +	/* If mode timing undefined, just return as no-op:
> +	 * Happens during initial modesetting of a crtc.
> +	 */
> +	if (mode->crtc_clock == 0) {
> +		DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
> +		WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
> +
> +		return false;
> +	}
> +
> +	/* Get current scanout position with system timestamp.
> +	 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
> +	 * if single query takes longer than max_error nanoseconds.
> +	 *
> +	 * This guarantees a tight bound on maximum error if
> +	 * code gets preempted or delayed for some reason.
> +	 */
> +	for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
> +		/*
> +		 * Get vertical and horizontal scanout position vpos, hpos,
> +		 * and bounding timestamps stime, etime, pre/post query.
> +		 */
> +		vbl_status = dev->driver->get_scanout_position(dev, pipe,
> +							       in_vblank_irq,
> +							       &vpos, &hpos,
> +							       &stime, &etime,
> +							       mode);
> +
> +		/* Return as no-op if scanout query unsupported or failed. */
> +		if (!vbl_status) {
> +			DRM_DEBUG("crtc %u : scanoutpos query failed.\n",
> +				  pipe);
> +			return false;
> +		}
> +
> +		/* Compute uncertainty in timestamp of scanout position query. */
> +		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
> +
> +		/* Accept result with <  max_error nsecs timing uncertainty. */
> +		if (duration_ns <= *max_error)
> +			break;
> +	}
> +
> +	/* Noisy system timing? */
> +	if (i == DRM_TIMESTAMP_MAXRETRIES) {
> +		DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n",
> +			  pipe, duration_ns/1000, *max_error/1000, i);
> +	}
> +
> +	/* Return upper bound of timestamp precision error. */
> +	*max_error = duration_ns;
> +
> +	/* Convert scanout position into elapsed time at raw_time query
> +	 * since start of scanout at first display scanline. delta_ns
> +	 * can be negative if start of scanout hasn't happened yet.
> +	 */
> +	delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
> +			   mode->crtc_clock);
> +
> +	if (!drm_timestamp_monotonic)
> +		etime = ktime_mono_to_real(etime);
> +
> +	/* save this only for debugging purposes */
> +	tv_etime = ktime_to_timeval(etime);
> +	/* Subtract time delta from raw timestamp to get final
> +	 * vblank_time timestamp for end of vblank.
> +	 */
> +	etime = ktime_sub_ns(etime, delta_ns);
> +	*vblank_time = ktime_to_timeval(etime);
> +
> +	DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
> +		      pipe, hpos, vpos,
> +		      (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
> +		      (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
> +		      duration_ns/1000, i);
> +
> +	return true;
> +}
> +EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
> +
> +static struct timeval get_drm_timestamp(void)
> +{
> +	ktime_t now;
> +
> +	now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
> +	return ktime_to_timeval(now);
> +}
> +
> +/**
> + * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
> + *                             vblank interval
> + * @dev: DRM device
> + * @pipe: index of CRTC whose vblank timestamp to retrieve
> + * @tvblank: Pointer to target struct timeval which should receive
> the timestamp
> + * @in_vblank_irq:
> + *     True when called from drm_crtc_handle_vblank().  Some drivers
> + *     need to apply some workarounds for gpu-specific vblank irq quirks
> + *     if flag is set.
> + *
> + * Fetches the system timestamp corresponding to the time of the most recent
> + * vblank interval on specified CRTC. May call into kms-driver to
> + * compute the timestamp with a high-precision GPU specific method.
> + *
> + * Returns zero if timestamp originates from uncorrected do_gettimeofday()
> + * call, i.e., it isn't very precisely locked to the true vblank.
> + *
> + * Returns:
> + * True if timestamp is considered to be very precise, false otherwise.
> + */
> +static bool
> +drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
> +			  struct timeval *tvblank, bool in_vblank_irq)
> +{
> +	bool ret = false;
> +
> +	/* Define requested maximum error on timestamps (nanoseconds). */
> +	int max_error = (int) drm_timestamp_precision * 1000;
> +
> +	/* Query driver if possible and precision timestamping enabled. */
> +	if (dev->driver->get_vblank_timestamp && (max_error > 0))
> +		ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error,
> +							tvblank, in_vblank_irq);
> +
> +	/* GPU high precision timestamp query unsupported or failed.
> +	 * Return current monotonic/gettimeofday timestamp as best estimate.
> +	 */
> +	if (!ret)
> +		*tvblank = get_drm_timestamp();
> +
> +	return ret;
> +}
> +
> +/**
> + * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
> + * @crtc: which counter to retrieve
> + *
> + * Fetches the "cooked" vblank count value that represents the number of
> + * vblank events since the system was booted, including lost events due to
> + * modesetting activity.
> + *
> + * Returns:
> + * The software vblank counter.
> + */
> +u32 drm_crtc_vblank_count(struct drm_crtc *crtc)
> +{
> +	return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
> +}
> +EXPORT_SYMBOL(drm_crtc_vblank_count);
> +
> +/**
> + * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the
> + *     system timestamp corresponding to that vblank counter value.
> + * @dev: DRM device
> + * @pipe: index of CRTC whose counter to retrieve
> + * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
> + *
> + * Fetches the "cooked" vblank count value that represents the number of
> + * vblank events since the system was booted, including lost events due to
> + * modesetting activity. Returns corresponding system timestamp of the time
> + * of the vblank interval that corresponds to the current vblank counter value.
> + *
> + * This is the legacy version of drm_crtc_vblank_count_and_time().
> + */
> +static u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
> +				     struct timeval *vblanktime)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	u32 vblank_count;
> +	unsigned int seq;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs)) {
> +		*vblanktime = (struct timeval) { 0 };
> +		return 0;
> +	}
> +
> +	do {
> +		seq = read_seqbegin(&vblank->seqlock);
> +		vblank_count = vblank->count;
> +		*vblanktime = vblank->time;
> +	} while (read_seqretry(&vblank->seqlock, seq));
> +
> +	return vblank_count;
> +}
> +
> +/**
> + * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
> + *     and the system timestamp corresponding to that vblank counter value
> + * @crtc: which counter to retrieve
> + * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
> + *
> + * Fetches the "cooked" vblank count value that represents the number of
> + * vblank events since the system was booted, including lost events due to
> + * modesetting activity. Returns corresponding system timestamp of the time
> + * of the vblank interval that corresponds to the current vblank counter value.
> + */
> +u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
> +				   struct timeval *vblanktime)
> +{
> +	return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
> +					 vblanktime);
> +}
> +EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
> +
> +static void send_vblank_event(struct drm_device *dev,
> +		struct drm_pending_vblank_event *e,
> +		unsigned long seq, struct timeval *now)
> +{
> +	e->event.sequence = seq;
> +	e->event.tv_sec = now->tv_sec;
> +	e->event.tv_usec = now->tv_usec;
> +
> +	trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe,
> +					 e->event.sequence);
> +
> +	drm_send_event_locked(dev, &e->base);
> +}
> +
> +/**
> + * drm_crtc_arm_vblank_event - arm vblank event after pageflip
> + * @crtc: the source CRTC of the vblank event
> + * @e: the event to send
> + *
> + * A lot of drivers need to generate vblank events for the very next vblank
> + * interrupt. For example when the page flip interrupt happens when the page
> + * flip gets armed, but not when it actually executes within the next vblank
> + * period. This helper function implements exactly the required vblank arming
> + * behaviour.
> + *
> + * NOTE: Drivers using this to send out the &drm_crtc_state.event as part of an
> + * atomic commit must ensure that the next vblank happens at exactly the same
> + * time as the atomic commit is committed to the hardware. This function itself
> + * does **not** protect again the next vblank interrupt racing with either this
> + * function call or the atomic commit operation. A possible sequence could be:
> + *
> + * 1. Driver commits new hardware state into vblank-synchronized registers.
> + * 2. A vblank happens, committing the hardware state. Also the corresponding
> + *    vblank interrupt is fired off and fully processed by the interrupt
> + *    handler.
> + * 3. The atomic commit operation proceeds to call drm_crtc_arm_vblank_event().
> + * 4. The event is only send out for the next vblank, which is wrong.
> + *
> + * An equivalent race can happen when the driver calls
> + * drm_crtc_arm_vblank_event() before writing out the new hardware state.
> + *
> + * The only way to make this work safely is to prevent the vblank from firing
> + * (and the hardware from committing anything else) until the entire atomic
> + * commit sequence has run to completion. If the hardware does not have such a
> + * feature (e.g. using a "go" bit), then it is unsafe to use this functions.
> + * Instead drivers need to manually send out the event from their interrupt
> + * handler by calling drm_crtc_send_vblank_event() and make sure that
> there's no
> + * possible race with the hardware committing the atomic update.
> + *
> + * Caller must hold event lock. Caller must also hold a vblank reference for
> + * the event @e, which will be dropped when the next vblank arrives.
> + */
> +void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
> +			       struct drm_pending_vblank_event *e)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	unsigned int pipe = drm_crtc_index(crtc);
> +
> +	assert_spin_locked(&dev->event_lock);
> +
> +	e->pipe = pipe;
> +	e->event.sequence = drm_vblank_count(dev, pipe);
> +	e->event.crtc_id = crtc->base.id;
> +	list_add_tail(&e->base.link, &dev->vblank_event_list);
> +}
> +EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
> +
> +/**
> + * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
> + * @crtc: the source CRTC of the vblank event
> + * @e: the event to send
> + *
> + * Updates sequence # and timestamp on event for the most recently processed
> + * vblank, and sends it to userspace.  Caller must hold event lock.
> + *
> + * See drm_crtc_arm_vblank_event() for a helper which can be used in certain
> + * situation, especially to send out events for atomic commit operations.
> + */
> +void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
> +				struct drm_pending_vblank_event *e)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	unsigned int seq, pipe = drm_crtc_index(crtc);
> +	struct timeval now;
> +
> +	if (dev->num_crtcs > 0) {
> +		seq = drm_vblank_count_and_time(dev, pipe, &now);
> +	} else {
> +		seq = 0;
> +
> +		now = get_drm_timestamp();
> +	}
> +	e->pipe = pipe;
> +	e->event.crtc_id = crtc->base.id;
> +	send_vblank_event(dev, e, seq, &now);
> +}
> +EXPORT_SYMBOL(drm_crtc_send_vblank_event);
> +
> +static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
> +{
> +	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> +		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> +
> +		if (crtc->funcs->enable_vblank)
> +			return crtc->funcs->enable_vblank(crtc);
> +	}
> +
> +	return dev->driver->enable_vblank(dev, pipe);
> +}
> +
> +/**
> + * drm_vblank_enable - enable the vblank interrupt on a CRTC
> + * @dev: DRM device
> + * @pipe: CRTC index
> + *
> + * Returns:
> + * Zero on success or a negative error code on failure.
> + */
> +static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	int ret = 0;
> +
> +	assert_spin_locked(&dev->vbl_lock);
> +
> +	spin_lock(&dev->vblank_time_lock);
> +
> +	if (!vblank->enabled) {
> +		/*
> +		 * Enable vblank irqs under vblank_time_lock protection.
> +		 * All vblank count & timestamp updates are held off
> +		 * until we are done reinitializing master counter and
> +		 * timestamps. Filtercode in drm_handle_vblank() will
> +		 * prevent double-accounting of same vblank interval.
> +		 */
> +		ret = __enable_vblank(dev, pipe);
> +		DRM_DEBUG("enabling vblank on crtc %u, ret: %d\n", pipe, ret);
> +		if (ret) {
> +			atomic_dec(&vblank->refcount);
> +		} else {
> +			drm_update_vblank_count(dev, pipe, 0);
> +			/* drm_update_vblank_count() includes a wmb so we just
> +			 * need to ensure that the compiler emits the write
> +			 * to mark the vblank as enabled after the call
> +			 * to drm_update_vblank_count().
> +			 */
> +			WRITE_ONCE(vblank->enabled, true);
> +		}
> +	}
> +
> +	spin_unlock(&dev->vblank_time_lock);
> +
> +	return ret;
> +}
> +
> +/**
> + * drm_vblank_get - get a reference count on vblank events
> + * @dev: DRM device
> + * @pipe: index of CRTC to own
> + *
> + * Acquire a reference count on vblank events to avoid having them disabled
> + * while in use.
> + *
> + * This is the legacy version of drm_crtc_vblank_get().
> + *
> + * Returns:
> + * Zero on success or a negative error code on failure.
> + */
> +static int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	unsigned long irqflags;
> +	int ret = 0;
> +
> +	if (!dev->num_crtcs)
> +		return -EINVAL;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return -EINVAL;
> +
> +	spin_lock_irqsave(&dev->vbl_lock, irqflags);
> +	/* Going from 0->1 means we have to enable interrupts again */
> +	if (atomic_add_return(1, &vblank->refcount) == 1) {
> +		ret = drm_vblank_enable(dev, pipe);
> +	} else {
> +		if (!vblank->enabled) {
> +			atomic_dec(&vblank->refcount);
> +			ret = -EINVAL;
> +		}
> +	}
> +	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> +
> +	return ret;
> +}
> +
> +/**
> + * drm_crtc_vblank_get - get a reference count on vblank events
> + * @crtc: which CRTC to own
> + *
> + * Acquire a reference count on vblank events to avoid having them disabled
> + * while in use.
> + *
> + * Returns:
> + * Zero on success or a negative error code on failure.
> + */
> +int drm_crtc_vblank_get(struct drm_crtc *crtc)
> +{
> +	return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
> +}
> +EXPORT_SYMBOL(drm_crtc_vblank_get);
> +
> +/**
> + * drm_vblank_put - release ownership of vblank events
> + * @dev: DRM device
> + * @pipe: index of CRTC to release
> + *
> + * Release ownership of a given vblank counter, turning off interrupts
> + * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
> + *
> + * This is the legacy version of drm_crtc_vblank_put().
> + */
> +static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return;
> +
> +	if (WARN_ON(atomic_read(&vblank->refcount) == 0))
> +		return;
> +
> +	/* Last user schedules interrupt disable */
> +	if (atomic_dec_and_test(&vblank->refcount)) {
> +		if (drm_vblank_offdelay == 0)
> +			return;
> +		else if (drm_vblank_offdelay < 0)
> +			vblank_disable_fn((unsigned long)vblank);
> +		else if (!dev->vblank_disable_immediate)
> +			mod_timer(&vblank->disable_timer,
> +				  jiffies + ((drm_vblank_offdelay * HZ)/1000));
> +	}
> +}
> +
> +/**
> + * drm_crtc_vblank_put - give up ownership of vblank events
> + * @crtc: which counter to give up
> + *
> + * Release ownership of a given vblank counter, turning off interrupts
> + * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
> + */
> +void drm_crtc_vblank_put(struct drm_crtc *crtc)
> +{
> +	drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
> +}
> +EXPORT_SYMBOL(drm_crtc_vblank_put);
> +
> +/**
> + * drm_wait_one_vblank - wait for one vblank
> + * @dev: DRM device
> + * @pipe: CRTC index
> + *
> + * This waits for one vblank to pass on @pipe, using the irq driver interfaces.
> + * It is a failure to call this when the vblank irq for @pipe is disabled, e.g.
> + * due to lack of driver support or because the crtc is off.
> + */
> +void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	int ret;
> +	u32 last;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return;
> +
> +	ret = drm_vblank_get(dev, pipe);
> +	if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", pipe, ret))
> +		return;
> +
> +	last = drm_vblank_count(dev, pipe);
> +
> +	ret = wait_event_timeout(vblank->queue,
> +				 last != drm_vblank_count(dev, pipe),
> +				 msecs_to_jiffies(100));
> +
> +	WARN(ret == 0, "vblank wait timed out on crtc %i\n", pipe);
> +
> +	drm_vblank_put(dev, pipe);
> +}
> +EXPORT_SYMBOL(drm_wait_one_vblank);
> +
> +/**
> + * drm_crtc_wait_one_vblank - wait for one vblank
> + * @crtc: DRM crtc
> + *
> + * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
> + * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
> + * due to lack of driver support or because the crtc is off.
> + */
> +void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
> +{
> +	drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
> +}
> +EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
> +
> +/**
> + * drm_crtc_vblank_off - disable vblank events on a CRTC
> + * @crtc: CRTC in question
> + *
> + * Drivers can use this function to shut down the vblank interrupt
> handling when
> + * disabling a crtc. This function ensures that the latest vblank
> frame count is
> + * stored so that drm_vblank_on can restore it again.
> + *
> + * Drivers must use this function when the hardware vblank counter can get
> + * reset, e.g. when suspending.
> + */
> +void drm_crtc_vblank_off(struct drm_crtc *crtc)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	unsigned int pipe = drm_crtc_index(crtc);
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	struct drm_pending_vblank_event *e, *t;
> +	struct timeval now;
> +	unsigned long irqflags;
> +	unsigned int seq;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return;
> +
> +	spin_lock_irqsave(&dev->event_lock, irqflags);
> +
> +	spin_lock(&dev->vbl_lock);
> +	DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
> +		      pipe, vblank->enabled, vblank->inmodeset);
> +
> +	/* Avoid redundant vblank disables without previous
> +	 * drm_crtc_vblank_on(). */
> +	if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
> +		drm_vblank_disable_and_save(dev, pipe);
> +
> +	wake_up(&vblank->queue);
> +
> +	/*
> +	 * Prevent subsequent drm_vblank_get() from re-enabling
> +	 * the vblank interrupt by bumping the refcount.
> +	 */
> +	if (!vblank->inmodeset) {
> +		atomic_inc(&vblank->refcount);
> +		vblank->inmodeset = 1;
> +	}
> +	spin_unlock(&dev->vbl_lock);
> +
> +	/* Send any queued vblank events, lest the natives grow disquiet */
> +	seq = drm_vblank_count_and_time(dev, pipe, &now);
> +
> +	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
> +		if (e->pipe != pipe)
> +			continue;
> +		DRM_DEBUG("Sending premature vblank event on disable: "
> +			  "wanted %u, current %u\n",
> +			  e->event.sequence, seq);
> +		list_del(&e->base.link);
> +		drm_vblank_put(dev, pipe);
> +		send_vblank_event(dev, e, seq, &now);
> +	}
> +	spin_unlock_irqrestore(&dev->event_lock, irqflags);
> +
> +	/* Will be reset by the modeset helpers when re-enabling the crtc by
> +	 * calling drm_calc_timestamping_constants(). */
> +	vblank->hwmode.crtc_clock = 0;
> +}
> +EXPORT_SYMBOL(drm_crtc_vblank_off);
> +
> +/**
> + * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
> + * @crtc: CRTC in question
> + *
> + * Drivers can use this function to reset the vblank state to off at load time.
> + * Drivers should use this together with the drm_crtc_vblank_off() and
> + * drm_crtc_vblank_on() functions. The difference compared to
> + * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
> + * and hence doesn't need to call any driver hooks.
> + */
> +void drm_crtc_vblank_reset(struct drm_crtc *crtc)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	unsigned long irqflags;
> +	unsigned int pipe = drm_crtc_index(crtc);
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +
> +	spin_lock_irqsave(&dev->vbl_lock, irqflags);
> +	/*
> +	 * Prevent subsequent drm_vblank_get() from enabling the vblank
> +	 * interrupt by bumping the refcount.
> +	 */
> +	if (!vblank->inmodeset) {
> +		atomic_inc(&vblank->refcount);
> +		vblank->inmodeset = 1;
> +	}
> +	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> +
> +	WARN_ON(!list_empty(&dev->vblank_event_list));
> +}
> +EXPORT_SYMBOL(drm_crtc_vblank_reset);
> +
> +/**
> + * drm_crtc_vblank_on - enable vblank events on a CRTC
> + * @crtc: CRTC in question
> + *
> + * This functions restores the vblank interrupt state captured with
> + * drm_crtc_vblank_off() again. Note that calls to drm_crtc_vblank_on() and
> + * drm_crtc_vblank_off() can be unbalanced and so can also be
> unconditionally called
> + * in driver load code to reflect the current hardware state of the crtc.
> + */
> +void drm_crtc_vblank_on(struct drm_crtc *crtc)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	unsigned int pipe = drm_crtc_index(crtc);
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	unsigned long irqflags;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return;
> +
> +	spin_lock_irqsave(&dev->vbl_lock, irqflags);
> +	DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
> +		      pipe, vblank->enabled, vblank->inmodeset);
> +
> +	/* Drop our private "prevent drm_vblank_get" refcount */
> +	if (vblank->inmodeset) {
> +		atomic_dec(&vblank->refcount);
> +		vblank->inmodeset = 0;
> +	}
> +
> +	drm_reset_vblank_timestamp(dev, pipe);
> +
> +	/*
> +	 * re-enable interrupts if there are users left, or the
> +	 * user wishes vblank interrupts to be enabled all the time.
> +	 */
> +	if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0)
> +		WARN_ON(drm_vblank_enable(dev, pipe));
> +	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> +}
> +EXPORT_SYMBOL(drm_crtc_vblank_on);
> +
> +static void drm_legacy_vblank_pre_modeset(struct drm_device *dev,
> +					  unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +
> +	/* vblank is not initialized (IRQ not installed ?), or has been freed */
> +	if (!dev->num_crtcs)
> +		return;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return;
> +
> +	/*
> +	 * To avoid all the problems that might happen if interrupts
> +	 * were enabled/disabled around or between these calls, we just
> +	 * have the kernel take a reference on the CRTC (just once though
> +	 * to avoid corrupting the count if multiple, mismatch calls occur),
> +	 * so that interrupts remain enabled in the interim.
> +	 */
> +	if (!vblank->inmodeset) {
> +		vblank->inmodeset = 0x1;
> +		if (drm_vblank_get(dev, pipe) == 0)
> +			vblank->inmodeset |= 0x2;
> +	}
> +}
> +
> +static void drm_legacy_vblank_post_modeset(struct drm_device *dev,
> +					   unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	unsigned long irqflags;
> +
> +	/* vblank is not initialized (IRQ not installed ?), or has been freed */
> +	if (!dev->num_crtcs)
> +		return;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return;
> +
> +	if (vblank->inmodeset) {
> +		spin_lock_irqsave(&dev->vbl_lock, irqflags);
> +		drm_reset_vblank_timestamp(dev, pipe);
> +		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> +
> +		if (vblank->inmodeset & 0x2)
> +			drm_vblank_put(dev, pipe);
> +
> +		vblank->inmodeset = 0;
> +	}
> +}
> +
> +int drm_legacy_modeset_ctl(struct drm_device *dev, void *data,
> +			   struct drm_file *file_priv)
> +{
> +	struct drm_modeset_ctl *modeset = data;
> +	unsigned int pipe;
> +
> +	/* If drm_vblank_init() hasn't been called yet, just no-op */
> +	if (!dev->num_crtcs)
> +		return 0;
> +
> +	/* KMS drivers handle this internally */
> +	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
> +		return 0;
> +
> +	pipe = modeset->crtc;
> +	if (pipe >= dev->num_crtcs)
> +		return -EINVAL;
> +
> +	switch (modeset->cmd) {
> +	case _DRM_PRE_MODESET:
> +		drm_legacy_vblank_pre_modeset(dev, pipe);
> +		break;
> +	case _DRM_POST_MODESET:
> +		drm_legacy_vblank_post_modeset(dev, pipe);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static inline bool vblank_passed(u32 seq, u32 ref)
> +{
> +	return (seq - ref) <= (1 << 23);
> +}
> +
> +static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
> +				  union drm_wait_vblank *vblwait,
> +				  struct drm_file *file_priv)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	struct drm_pending_vblank_event *e;
> +	struct timeval now;
> +	unsigned long flags;
> +	unsigned int seq;
> +	int ret;
> +
> +	e = kzalloc(sizeof(*e), GFP_KERNEL);
> +	if (e == NULL) {
> +		ret = -ENOMEM;
> +		goto err_put;
> +	}
> +
> +	e->pipe = pipe;
> +	e->event.base.type = DRM_EVENT_VBLANK;
> +	e->event.base.length = sizeof(e->event);
> +	e->event.user_data = vblwait->request.signal;
> +
> +	spin_lock_irqsave(&dev->event_lock, flags);
> +
> +	/*
> +	 * drm_crtc_vblank_off() might have been called after we called
> +	 * drm_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
> +	 * vblank disable, so no need for further locking.  The reference from
> +	 * drm_vblank_get() protects against vblank disable from another source.
> +	 */
> +	if (!READ_ONCE(vblank->enabled)) {
> +		ret = -EINVAL;
> +		goto err_unlock;
> +	}
> +
> +	ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
> +					    &e->event.base);
> +
> +	if (ret)
> +		goto err_unlock;
> +
> +	seq = drm_vblank_count_and_time(dev, pipe, &now);
> +
> +	DRM_DEBUG("event on vblank count %u, current %u, crtc %u\n",
> +		  vblwait->request.sequence, seq, pipe);
> +
> +	trace_drm_vblank_event_queued(file_priv, pipe,
> +				      vblwait->request.sequence);
> +
> +	e->event.sequence = vblwait->request.sequence;
> +	if (vblank_passed(seq, vblwait->request.sequence)) {
> +		drm_vblank_put(dev, pipe);
> +		send_vblank_event(dev, e, seq, &now);
> +		vblwait->reply.sequence = seq;
> +	} else {
> +		/* drm_handle_vblank_events will call drm_vblank_put */
> +		list_add_tail(&e->base.link, &dev->vblank_event_list);
> +		vblwait->reply.sequence = vblwait->request.sequence;
> +	}
> +
> +	spin_unlock_irqrestore(&dev->event_lock, flags);
> +
> +	return 0;
> +
> +err_unlock:
> +	spin_unlock_irqrestore(&dev->event_lock, flags);
> +	kfree(e);
> +err_put:
> +	drm_vblank_put(dev, pipe);
> +	return ret;
> +}
> +
> +static bool drm_wait_vblank_is_query(union drm_wait_vblank *vblwait)
> +{
> +	if (vblwait->request.sequence)
> +		return false;
> +
> +	return _DRM_VBLANK_RELATIVE ==
> +		(vblwait->request.type & (_DRM_VBLANK_TYPES_MASK |
> +					  _DRM_VBLANK_EVENT |
> +					  _DRM_VBLANK_NEXTONMISS));
> +}
> +
> +/*
> + * Wait for VBLANK.
> + *
> + * \param inode device inode.
> + * \param file_priv DRM file private.
> + * \param cmd command.
> + * \param data user argument, pointing to a drm_wait_vblank structure.
> + * \return zero on success or a negative number on failure.
> + *
> + * This function enables the vblank interrupt on the pipe requested, then
> + * sleeps waiting for the requested sequence number to occur, and drops
> + * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
> + * after a timeout with no further vblank waits scheduled).
> + */
> +int drm_wait_vblank(struct drm_device *dev, void *data,
> +		    struct drm_file *file_priv)
> +{
> +	struct drm_vblank_crtc *vblank;
> +	union drm_wait_vblank *vblwait = data;
> +	int ret;
> +	unsigned int flags, seq, pipe, high_pipe;
> +
> +	if (!dev->irq_enabled)
> +		return -EINVAL;
> +
> +	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
> +		return -EINVAL;
> +
> +	if (vblwait->request.type &
> +	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
> +	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
> +		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
> +			  vblwait->request.type,
> +			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
> +			   _DRM_VBLANK_HIGH_CRTC_MASK));
> +		return -EINVAL;
> +	}
> +
> +	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
> +	high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
> +	if (high_pipe)
> +		pipe = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
> +	else
> +		pipe = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
> +	if (pipe >= dev->num_crtcs)
> +		return -EINVAL;
> +
> +	vblank = &dev->vblank[pipe];
> +
> +	/* If the counter is currently enabled and accurate, short-circuit
> +	 * queries to return the cached timestamp of the last vblank.
> +	 */
> +	if (dev->vblank_disable_immediate &&
> +	    drm_wait_vblank_is_query(vblwait) &&
> +	    READ_ONCE(vblank->enabled)) {
> +		struct timeval now;
> +
> +		vblwait->reply.sequence =
> +			drm_vblank_count_and_time(dev, pipe, &now);
> +		vblwait->reply.tval_sec = now.tv_sec;
> +		vblwait->reply.tval_usec = now.tv_usec;
> +		return 0;
> +	}
> +
> +	ret = drm_vblank_get(dev, pipe);
> +	if (ret) {
> +		DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
> +		return ret;
> +	}
> +	seq = drm_vblank_count(dev, pipe);
> +
> +	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
> +	case _DRM_VBLANK_RELATIVE:
> +		vblwait->request.sequence += seq;
> +		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
> +	case _DRM_VBLANK_ABSOLUTE:
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		goto done;
> +	}
> +
> +	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
> +	    vblank_passed(seq, vblwait->request.sequence))
> +		vblwait->request.sequence = seq + 1;
> +
> +	if (flags & _DRM_VBLANK_EVENT) {
> +		/* must hold on to the vblank ref until the event fires
> +		 * drm_vblank_put will be called asynchronously
> +		 */
> +		return drm_queue_vblank_event(dev, pipe, vblwait, file_priv);
> +	}
> +
> +	if (vblwait->request.sequence != seq) {
> +		DRM_DEBUG("waiting on vblank count %u, crtc %u\n",
> +			  vblwait->request.sequence, pipe);
> +		DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
> +			    vblank_passed(drm_vblank_count(dev, pipe),
> +					  vblwait->request.sequence) ||
> +			    !READ_ONCE(vblank->enabled));
> +	}
> +
> +	if (ret != -EINTR) {
> +		struct timeval now;
> +
> +		vblwait->reply.sequence = drm_vblank_count_and_time(dev, pipe, &now);
> +		vblwait->reply.tval_sec = now.tv_sec;
> +		vblwait->reply.tval_usec = now.tv_usec;
> +
> +		DRM_DEBUG("crtc %d returning %u to client\n",
> +			  pipe, vblwait->reply.sequence);
> +	} else {
> +		DRM_DEBUG("crtc %d vblank wait interrupted by signal\n", pipe);
> +	}
> +
> +done:
> +	drm_vblank_put(dev, pipe);
> +	return ret;
> +}
> +
> +static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
> +{
> +	struct drm_pending_vblank_event *e, *t;
> +	struct timeval now;
> +	unsigned int seq;
> +
> +	assert_spin_locked(&dev->event_lock);
> +
> +	seq = drm_vblank_count_and_time(dev, pipe, &now);
> +
> +	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
> +		if (e->pipe != pipe)
> +			continue;
> +		if (!vblank_passed(seq, e->event.sequence))
> +			continue;
> +
> +		DRM_DEBUG("vblank event on %u, current %u\n",
> +			  e->event.sequence, seq);
> +
> +		list_del(&e->base.link);
> +		drm_vblank_put(dev, pipe);
> +		send_vblank_event(dev, e, seq, &now);
> +	}
> +
> +	trace_drm_vblank_event(pipe, seq);
> +}
> +
> +/**
> + * drm_handle_vblank - handle a vblank event
> + * @dev: DRM device
> + * @pipe: index of CRTC where this event occurred
> + *
> + * Drivers should call this routine in their vblank interrupt handlers to
> + * update the vblank counter and send any signals that may be pending.
> + *
> + * This is the legacy version of drm_crtc_handle_vblank().
> + */
> +bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
> +{
> +	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> +	unsigned long irqflags;
> +	bool disable_irq;
> +
> +	if (WARN_ON_ONCE(!dev->num_crtcs))
> +		return false;
> +
> +	if (WARN_ON(pipe >= dev->num_crtcs))
> +		return false;
> +
> +	spin_lock_irqsave(&dev->event_lock, irqflags);
> +
> +	/* Need timestamp lock to prevent concurrent execution with
> +	 * vblank enable/disable, as this would cause inconsistent
> +	 * or corrupted timestamps and vblank counts.
> +	 */
> +	spin_lock(&dev->vblank_time_lock);
> +
> +	/* Vblank irq handling disabled. Nothing to do. */
> +	if (!vblank->enabled) {
> +		spin_unlock(&dev->vblank_time_lock);
> +		spin_unlock_irqrestore(&dev->event_lock, irqflags);
> +		return false;
> +	}
> +
> +	drm_update_vblank_count(dev, pipe, true);
> +
> +	spin_unlock(&dev->vblank_time_lock);
> +
> +	wake_up(&vblank->queue);
> +
> +	/* With instant-off, we defer disabling the interrupt until after
> +	 * we finish processing the following vblank after all events have
> +	 * been signaled. The disable has to be last (after
> +	 * drm_handle_vblank_events) so that the timestamp is always accurate.
> +	 */
> +	disable_irq = (dev->vblank_disable_immediate &&
> +		       drm_vblank_offdelay > 0 &&
> +		       !atomic_read(&vblank->refcount));
> +
> +	drm_handle_vblank_events(dev, pipe);
> +
> +	spin_unlock_irqrestore(&dev->event_lock, irqflags);
> +
> +	if (disable_irq)
> +		vblank_disable_fn((unsigned long)vblank);
> +
> +	return true;
> +}
> +EXPORT_SYMBOL(drm_handle_vblank);
> +
> +/**
> + * drm_crtc_handle_vblank - handle a vblank event
> + * @crtc: where this event occurred
> + *
> + * Drivers should call this routine in their vblank interrupt handlers to
> + * update the vblank counter and send any signals that may be pending.
> + *
> + * This is the native KMS version of drm_handle_vblank().
> + *
> + * Returns:
> + * True if the event was successfully handled, false on failure.
> + */
> +bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
> +{
> +	return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
> +}
> +EXPORT_SYMBOL(drm_crtc_handle_vblank);
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index c363f2fdff31..2e0b76cceb97 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -80,6 +80,9 @@
>  #include <drm/drm_debugfs.h>
>  #include <drm/drm_ioctl.h>
>  #include <drm/drm_sysfs.h>
> +#include <drm/drm_vblank.h>
> +#include <drm/drm_irq.h>
> +
>  
>  struct module;
>  
> @@ -447,8 +450,6 @@ static inline bool
> drm_drv_uses_atomic_modeset(struct drm_device *dev)
>  	return dev->mode_config.funcs->atomic_commit != NULL;
>  }
>  
> -#include <drm/drm_irq.h>
> -
>  #define DRM_SWITCH_POWER_ON 0
>  #define DRM_SWITCH_POWER_OFF 1
>  #define DRM_SWITCH_POWER_CHANGING 2
> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> index 5dd27ae5c47c..d66f7ee07fb5 100644
> --- a/include/drm/drm_file.h
> +++ b/include/drm/drm_file.h
> @@ -40,6 +40,7 @@
>  struct dma_fence;
>  struct drm_file;
>  struct drm_device;
> +struct device;
>  
>  /*
>   * FIXME: Not sure we want to have drm_minor here in the end, but to avoid
> diff --git a/include/drm/drm_irq.h b/include/drm/drm_irq.h
> index 569ca86d4e1f..d77f6e65b1c6 100644
> --- a/include/drm/drm_irq.h
> +++ b/include/drm/drm_irq.h
> @@ -24,165 +24,9 @@
>  #ifndef _DRM_IRQ_H_
>  #define _DRM_IRQ_H_
>  
> -#include <linux/seqlock.h>
> -
> -/**
> - * struct drm_pending_vblank_event - pending vblank event tracking
> - */
> -struct drm_pending_vblank_event {
> -	/**
> -	 * @base: Base structure for tracking pending DRM events.
> -	 */
> -	struct drm_pending_event base;
> -	/**
> -	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
> -	 */
> -	unsigned int pipe;
> -	/**
> -	 * @event: Actual event which will be sent to userspace.
> -	 */
> -	struct drm_event_vblank event;
> -};
> -
> -/**
> - * struct drm_vblank_crtc - vblank tracking for a CRTC
> - *
> - * This structure tracks the vblank state for one CRTC.
> - *
> - * Note that for historical reasons - the vblank handling code is still shared
> - * with legacy/non-kms drivers - this is a free-standing structure not directly
> - * connected to &struct drm_crtc. But all public interface functions are taking
> - * a &struct drm_crtc to hide this implementation detail.
> - */
> -struct drm_vblank_crtc {
> -	/**
> -	 * @dev: Pointer to the &drm_device.
> -	 */
> -	struct drm_device *dev;
> -	/**
> -	 * @queue: Wait queue for vblank waiters.
> -	 */
> -	wait_queue_head_t queue;	/**< VBLANK wait queue */
> -	/**
> -	 * @disable_timer: Disable timer for the delayed vblank disabling
> -	 * hysteresis logic. Vblank disabling is controlled through the
> -	 * drm_vblank_offdelay module option and the setting of the
> -	 * &drm_device.max_vblank_count value.
> -	 */
> -	struct timer_list disable_timer;
> -
> -	/**
> -	 * @seqlock: Protect vblank count and time.
> -	 */
> -	seqlock_t seqlock;		/* protects vblank count and time */
> -
> -	/**
> -	 * @count: Current software vblank counter.
> -	 */
> -	u32 count;
> -	/**
> -	 * @time: Vblank timestamp corresponding to @count.
> -	 */
> -	struct timeval time;
> -
> -	/**
> -	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
> -	 * this refcount reaches 0 can the hardware interrupt be disabled using
> -	 * @disable_timer.
> -	 */
> -	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
> -	/**
> -	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
> -	 */
> -	u32 last;
> -	/**
> -	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
> -	 * For legacy driver bit 2 additionally tracks whether an additional
> -	 * temporary vblank reference has been acquired to paper over the
> -	 * hardware counter resetting/jumping. KMS drivers should instead just
> -	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
> -	 * save and restore the vblank count.
> -	 */
> -	unsigned int inmodeset;		/* Display driver is setting mode */
> -	/**
> -	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
> -	 * structure.
> -	 */
> -	unsigned int pipe;
> -	/**
> -	 * @framedur_ns: Frame/Field duration in ns, used by
> -	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
> -	 * drm_calc_timestamping_constants().
> -	 */
> -	int framedur_ns;
> -	/**
> -	 * @linedur_ns: Line duration in ns, used by
> -	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
> -	 * drm_calc_timestamping_constants().
> -	 */
> -	int linedur_ns;
> -
> -	/**
> -	 * @hwmode:
> -	 *
> -	 * Cache of the current hardware display mode. Only valid when @enabled
> -	 * is set. This is used by helpers like
> -	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
> -	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
> -	 * because that one is really hard to get from interrupt context.
> -	 */
> -	struct drm_display_mode hwmode;
> -
> -	/**
> -	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
> -	 * avoid double-disabling and hence corrupting saved state. Needed by
> -	 * drivers not using atomic KMS, since those might go through their CRTC
> -	 * disabling functions multiple times.
> -	 */
> -	bool enabled;
> -};
> +struct drm_device;
>  
>  int drm_irq_install(struct drm_device *dev, int irq);
>  int drm_irq_uninstall(struct drm_device *dev);
>  
> -int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
> -u32 drm_crtc_vblank_count(struct drm_crtc *crtc);
> -u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
> -				   struct timeval *vblanktime);
> -void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
> -			       struct drm_pending_vblank_event *e);
> -void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
> -			      struct drm_pending_vblank_event *e);
> -bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
> -bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
> -int drm_crtc_vblank_get(struct drm_crtc *crtc);
> -void drm_crtc_vblank_put(struct drm_crtc *crtc);
> -void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
> -void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
> -void drm_crtc_vblank_off(struct drm_crtc *crtc);
> -void drm_crtc_vblank_reset(struct drm_crtc *crtc);
> -void drm_crtc_vblank_on(struct drm_crtc *crtc);
> -void drm_vblank_cleanup(struct drm_device *dev);
> -u32 drm_accurate_vblank_count(struct drm_crtc *crtc);
> -
> -bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
> -					   unsigned int pipe, int *max_error,
> -					   struct timeval *vblank_time,
> -					   bool in_vblank_irq);
> -void drm_calc_timestamping_constants(struct drm_crtc *crtc,
> -				     const struct drm_display_mode *mode);
> -
> -/**
> - * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
> - * @crtc: which CRTC's vblank waitqueue to retrieve
> - *
> - * This function returns a pointer to the vblank waitqueue for the CRTC.
> - * Drivers can use this to implement vblank waits using wait_event()
> and related
> - * functions.
> - */
> -static inline wait_queue_head_t *drm_crtc_vblank_waitqueue(struct
> drm_crtc *crtc)
> -{
> -	return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
> -}
> -
>  #endif
> diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h
> index 59ccab402e85..9cd9e36f77b5 100644
> --- a/include/drm/drm_prime.h
> +++ b/include/drm/drm_prime.h
> @@ -59,6 +59,8 @@ struct drm_device;
>  struct drm_gem_object;
>  struct drm_file;
>  
> +struct device;
> +
>  struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
>  				     struct drm_gem_object *obj,
>  				     int flags);
> diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h
> new file mode 100644
> index 000000000000..4cde47332dfa
> --- /dev/null
> +++ b/include/drm/drm_vblank.h
> @@ -0,0 +1,181 @@
> +/*
> + * Copyright 2016 Intel Corp.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + */
> +
> +#ifndef _DRM_VBLANK_H_
> +#define _DRM_VBLANK_H_
> +
> +#include <linux/seqlock.h>
> +#include <linux/idr.h>
> +#include <linux/poll.h>
> +
> +#include <drm/drm_file.h>
> +#include <drm/drm_modes.h>
> +#include <uapi/drm/drm.h>
> +
> +struct drm_device;
> +struct drm_crtc;
> +
> +/**
> + * struct drm_pending_vblank_event - pending vblank event tracking
> + */
> +struct drm_pending_vblank_event {
> +	/**
> +	 * @base: Base structure for tracking pending DRM events.
> +	 */
> +	struct drm_pending_event base;
> +	/**
> +	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
> +	 */
> +	unsigned int pipe;
> +	/**
> +	 * @event: Actual event which will be sent to userspace.
> +	 */
> +	struct drm_event_vblank event;
> +};
> +
> +/**
> + * struct drm_vblank_crtc - vblank tracking for a CRTC
> + *
> + * This structure tracks the vblank state for one CRTC.
> + *
> + * Note that for historical reasons - the vblank handling code is still shared
> + * with legacy/non-kms drivers - this is a free-standing structure not directly
> + * connected to &struct drm_crtc. But all public interface functions are taking
> + * a &struct drm_crtc to hide this implementation detail.
> + */
> +struct drm_vblank_crtc {
> +	/**
> +	 * @dev: Pointer to the &drm_device.
> +	 */
> +	struct drm_device *dev;
> +	/**
> +	 * @queue: Wait queue for vblank waiters.
> +	 */
> +	wait_queue_head_t queue;	/**< VBLANK wait queue */
> +	/**
> +	 * @disable_timer: Disable timer for the delayed vblank disabling
> +	 * hysteresis logic. Vblank disabling is controlled through the
> +	 * drm_vblank_offdelay module option and the setting of the
> +	 * &drm_device.max_vblank_count value.
> +	 */
> +	struct timer_list disable_timer;
> +
> +	/**
> +	 * @seqlock: Protect vblank count and time.
> +	 */
> +	seqlock_t seqlock;		/* protects vblank count and time */
> +
> +	/**
> +	 * @count: Current software vblank counter.
> +	 */
> +	u32 count;
> +	/**
> +	 * @time: Vblank timestamp corresponding to @count.
> +	 */
> +	struct timeval time;
> +
> +	/**
> +	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
> +	 * this refcount reaches 0 can the hardware interrupt be disabled using
> +	 * @disable_timer.
> +	 */
> +	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
> +	/**
> +	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
> +	 */
> +	u32 last;
> +	/**
> +	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
> +	 * For legacy driver bit 2 additionally tracks whether an additional
> +	 * temporary vblank reference has been acquired to paper over the
> +	 * hardware counter resetting/jumping. KMS drivers should instead just
> +	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
> +	 * save and restore the vblank count.
> +	 */
> +	unsigned int inmodeset;		/* Display driver is setting mode */
> +	/**
> +	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
> +	 * structure.
> +	 */
> +	unsigned int pipe;
> +	/**
> +	 * @framedur_ns: Frame/Field duration in ns, used by
> +	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
> +	 * drm_calc_timestamping_constants().
> +	 */
> +	int framedur_ns;
> +	/**
> +	 * @linedur_ns: Line duration in ns, used by
> +	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
> +	 * drm_calc_timestamping_constants().
> +	 */
> +	int linedur_ns;
> +
> +	/**
> +	 * @hwmode:
> +	 *
> +	 * Cache of the current hardware display mode. Only valid when @enabled
> +	 * is set. This is used by helpers like
> +	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
> +	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
> +	 * because that one is really hard to get from interrupt context.
> +	 */
> +	struct drm_display_mode hwmode;
> +
> +	/**
> +	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
> +	 * avoid double-disabling and hence corrupting saved state. Needed by
> +	 * drivers not using atomic KMS, since those might go through their CRTC
> +	 * disabling functions multiple times.
> +	 */
> +	bool enabled;
> +};
> +
> +int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
> +u32 drm_crtc_vblank_count(struct drm_crtc *crtc);
> +u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
> +				   struct timeval *vblanktime);
> +void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
> +			       struct drm_pending_vblank_event *e);
> +void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
> +			      struct drm_pending_vblank_event *e);
> +bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
> +bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
> +int drm_crtc_vblank_get(struct drm_crtc *crtc);
> +void drm_crtc_vblank_put(struct drm_crtc *crtc);
> +void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
> +void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
> +void drm_crtc_vblank_off(struct drm_crtc *crtc);
> +void drm_crtc_vblank_reset(struct drm_crtc *crtc);
> +void drm_crtc_vblank_on(struct drm_crtc *crtc);
> +void drm_vblank_cleanup(struct drm_device *dev);
> +u32 drm_accurate_vblank_count(struct drm_crtc *crtc);
> +
> +bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
> +					   unsigned int pipe, int *max_error,
> +					   struct timeval *vblank_time,
> +					   bool in_vblank_irq);
> +void drm_calc_timestamping_constants(struct drm_crtc *crtc,
> +				     const struct drm_display_mode *mode);
> +wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
> +#endif


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