[PATCH V3] drm/vkms: Add vblank events simulated by hrtimers

Daniel Vetter daniel at ffwll.ch
Wed Jul 11 07:23:15 UTC 2018


On Tue, Jul 10, 2018 at 10:48:57PM -0300, Rodrigo Siqueira wrote:
> This commit adds regular vblank events simulated through hrtimers, which
> is a feature required by VKMS to mimic real hardware. Additionally, all
> the vblank event send after pageflip is kept in the atomic_flush
> function.
> 
> Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
> ---
> Changes since v1:
> - Removes hardcoded vblank interval to get it from user space
> - Compute the vblank timer interval per interruption
> 
> Changes since v2:
> - Removes unnecessary algorithm to compute the next period
> - Uses drm_calc_timestamping_constants to get the vblank interval
>   instead of calculating it manually
> - Adds disable_vblank helper that turns of crtc
> - Simplifies implementation by using drm_crtc_arm_vblank_event
> - Replaces the code in atomic_begin to atomic_flush
> - Removes unnecessary field in vkms_output
> 
>  drivers/gpu/drm/vkms/vkms_crtc.c | 88 +++++++++++++++++++++++++++++++-
>  drivers/gpu/drm/vkms/vkms_drv.c  |  9 ++++
>  drivers/gpu/drm/vkms/vkms_drv.h  | 15 ++++++
>  3 files changed, 110 insertions(+), 2 deletions(-)

Patch looks good, but doesn't apply cleanly on top of drm-misc-next. Can
you please rebase (and if there's other patches this patch depends upon,
please resend those too).

Thanks, Daniel
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> index 84cc05506b09..bc9beccb977e 100644
> --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> @@ -10,6 +10,60 @@
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_crtc_helper.h>
>  
> +static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
> +{
> +	struct vkms_output *output = container_of(timer, struct vkms_output,
> +						  vblank_hrtimer);
> +	struct drm_crtc *crtc = &output->crtc;
> +	int ret_overrun;
> +	bool ret;
> +
> +	ret = drm_crtc_handle_vblank(crtc);
> +	if (!ret)
> +		DRM_ERROR("vkms failure on handling vblank");
> +
> +	ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
> +					  output->period_ns);
> +
> +	return HRTIMER_RESTART;
> +}
> +
> +static int vkms_enable_vblank(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 vkms_output *out = drm_crtc_to_vkms_output(crtc);
> +
> +	drm_calc_timestamping_constants(crtc, &crtc->mode);
> +
> +	hrtimer_init(&out->vblank_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> +	out->vblank_hrtimer.function = &vkms_vblank_simulate;
> +	out->period_ns = ktime_set(0, vblank->framedur_ns);
> +	hrtimer_start(&out->vblank_hrtimer, out->period_ns, HRTIMER_MODE_REL);
> +
> +	return 0;
> +}
> +
> +static void vkms_disable_vblank(struct drm_crtc *crtc)
> +{
> +	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
> +
> +	hrtimer_cancel(&out->vblank_hrtimer);
> +}
> +
> +bool vkms_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
> +			       int *max_error, ktime_t *vblank_time,
> +			       bool in_vblank_irq)
> +{
> +	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
> +	struct vkms_output *output = &vkmsdev->output;
> +
> +	*vblank_time = output->vblank_hrtimer.node.expires;
> +
> +	return true;
> +}
> +
>  static const struct drm_crtc_funcs vkms_crtc_funcs = {
>  	.set_config             = drm_atomic_helper_set_config,
>  	.destroy                = drm_crtc_cleanup,
> @@ -17,6 +71,8 @@ static const struct drm_crtc_funcs vkms_crtc_funcs = {
>  	.reset                  = drm_atomic_helper_crtc_reset,
>  	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
>  	.atomic_destroy_state   = drm_atomic_helper_crtc_destroy_state,
> +	.enable_vblank		= vkms_enable_vblank,
> +	.disable_vblank		= vkms_disable_vblank,
>  };
>  
>  static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
> @@ -28,11 +84,39 @@ static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
>  static void vkms_crtc_atomic_enable(struct drm_crtc *crtc,
>  				    struct drm_crtc_state *old_state)
>  {
> +	drm_crtc_vblank_on(crtc);
> +}
> +
> +static void vkms_crtc_atomic_disable(struct drm_crtc *crtc,
> +				     struct drm_crtc_state *old_state)
> +{
> +	drm_crtc_vblank_off(crtc);
> +}
> +
> +static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
> +				   struct drm_crtc_state *old_crtc_state)
> +{
> +	unsigned long flags;
> +
> +	if (crtc->state->event) {
> +		spin_lock_irqsave(&crtc->dev->event_lock, flags);
> +
> +		if (drm_crtc_vblank_get(crtc) != 0)
> +			drm_crtc_send_vblank_event(crtc, crtc->state->event);
> +		else
> +			drm_crtc_arm_vblank_event(crtc, crtc->state->event);
> +
> +		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> +
> +		crtc->state->event = NULL;
> +	}
>  }
>  
>  static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = {
> -	.atomic_check  = vkms_crtc_atomic_check,
> -	.atomic_enable = vkms_crtc_atomic_enable,
> +	.atomic_check	= vkms_crtc_atomic_check,
> +	.atomic_flush	= vkms_crtc_atomic_flush,
> +	.atomic_enable	= vkms_crtc_atomic_enable,
> +	.atomic_disable	= vkms_crtc_atomic_disable,
>  };
>  
>  int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> index fe93f8c17997..6368048c6e54 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> @@ -55,6 +55,7 @@ static struct drm_driver vkms_driver = {
>  	.dumb_create		= vkms_dumb_create,
>  	.dumb_map_offset	= vkms_dumb_map,
>  	.gem_vm_ops		= &vkms_gem_vm_ops,
> +	.get_vblank_timestamp	= vkms_get_vblank_timestamp,
>  
>  	.name			= DRIVER_NAME,
>  	.desc			= DRIVER_DESC,
> @@ -102,6 +103,14 @@ static int __init vkms_init(void)
>  		goto out_fini;
>  	}
>  
> +	vkms_device->drm.irq_enabled = true;
> +
> +	ret = drm_vblank_init(&vkms_device->drm, 1);
> +	if (ret) {
> +		DRM_ERROR("Failed to vblank\n");
> +		goto out_fini;
> +	}
> +
>  	ret = vkms_modeset_init(vkms_device);
>  	if (ret)
>  		goto out_unregister;
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> index 76f1720f81a5..18a02b3908ff 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.h
> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> @@ -5,6 +5,7 @@
>  #include <drm/drm.h>
>  #include <drm/drm_gem.h>
>  #include <drm/drm_encoder.h>
> +#include <linux/hrtimer.h>
>  
>  #define XRES_MIN    32
>  #define YRES_MIN    32
> @@ -23,6 +24,9 @@ struct vkms_output {
>  	struct drm_crtc crtc;
>  	struct drm_encoder encoder;
>  	struct drm_connector connector;
> +	struct hrtimer vblank_hrtimer;
> +	ktime_t period_ns;
> +	struct drm_pending_vblank_event *event;
>  };
>  
>  struct vkms_device {
> @@ -37,9 +41,20 @@ struct vkms_gem_object {
>  	struct page **pages;
>  };
>  
> +#define drm_crtc_to_vkms_output(target) \
> +	container_of(target, struct vkms_output, crtc)
> +
> +#define drm_device_to_vkms_device(target) \
> +	container_of(target, struct vkms_device, drm)
> +
> +/* CRTC */
>  int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
>  		   struct drm_plane *primary, struct drm_plane *cursor);
>  
> +bool vkms_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
> +			       int *max_error, ktime_t *vblank_time,
> +			       bool in_vblank_irq);
> +
>  int vkms_output_init(struct vkms_device *vkmsdev);
>  
>  struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev);
> -- 
> 2.18.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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