[Intel-gfx] [PATCH 3/4] drm/i915: enable VT switchless resume v3

[Knut Petersen]

On 26.03.2013 17:25, Jesse Barnes wrote:
> With the other bits in place, we can do this safely.
>
> v2: disable backlight on suspend to prevent premature enablement on resume
> v3: disable CRTCs on suspend to allow RTD3 (Kristen)
>
> Signed-off-by: Jesse Barnes<jbarnes at virtuousgeek.org>

I might be a bit late as your patch has long be accepted, but it introduced
a regression. Steps to reproduce the problem:

boot linux,
startx,
suspend (s3),
resume,
terminate xserver,
startx,
mplayer -fs foo.video

Prior to your patch, everything worked fine. With your patch, the xserver starts much slowler,
the monitor is switched off and on again, the kde splash screen is displayed in the upper
left corner (1024x768) on my 1280x1024 monitor. mplayer -fs plays a video correctly, but
the (normally) black bars above and below the video contain garbage for x > ~1024 / y > ~768

Reproducibility: 100% on my system.

Hardware: AOpen i915GMm-hfs, Pentium-M Dothan, Eizo Flexscan L557 monitor

00:02.0 VGA compatible controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 04) (prog-if 00 [VGA controller])
         Subsystem: AOPEN Inc. Device 0554
         Flags: bus master, fast devsel, latency 0, IRQ 16
         Memory at d5300000 (32-bit, non-prefetchable) [size=512K]
         I/O ports at e400 [size=8]
         Memory at c0000000 (32-bit, prefetchable) [size=256M]
         Memory at d5400000 (32-bit, non-prefetchable) [size=256K]
         Expansion ROM at <unassigned> [disabled]
         Capabilities: [d0] Power Management version 2
         Kernel driver in use: i915

00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 04)
         Subsystem: AOPEN Inc. Device 0554
         Flags: bus master, fast devsel, latency 0
         Memory at d5380000 (32-bit, non-prefetchable) [size=512K]
         Capabilities: [d0] Power Management version 2

Software: openSuSE 13.1, current git xorg.

last good mainline linux kernel: 3.9.y
kernels affected: 3.10.y, 3.11.y, 3.12.y, 3.13.y, 3.14.y, 3.15-rc2

Attached is a patch against 3.14.1. Directly reverting 24576d2 is impossible as a helper
function was eliminated, a file was renamed, and other patches touched the code, but
more or less my patch is simply a functional revert of yours. At least here it cures the problem ...

cu,
  Knut


> ---
>   drivers/gpu/drm/i915/i915_drv.c |   14 +++++++++++---
>   drivers/gpu/drm/i915/intel_fb.c |    3 +++
>   2 files changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 6c4b13c..bf57e1c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -458,6 +458,7 @@ bool i915_semaphore_is_enabled(struct drm_device *dev)
>   static int i915_drm_freeze(struct drm_device *dev)
>   {
>   	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_crtc *crtc;
>   
>   	/* ignore lid events during suspend */
>   	mutex_lock(&dev_priv->modeset_restore_lock);
> @@ -481,10 +482,14 @@ static int i915_drm_freeze(struct drm_device *dev)
>   
>   		cancel_delayed_work_sync(&dev_priv->rps.delayed_resume_work);
>   
> -		intel_modeset_disable(dev);
> -
>   		drm_irq_uninstall(dev);
>   		dev_priv->enable_hotplug_processing = false;
> +		/*
> +		 * Disable CRTCs directly since we want to preserve sw state
> +		 * for _thaw.
> +		 */
> +		list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
> +			dev_priv->display.crtc_disable(crtc);
>   	}
>   
>   	i915_save_state(dev);
> @@ -562,7 +567,10 @@ static int __i915_drm_thaw(struct drm_device *dev)
>   		drm_irq_install(dev);
>   
>   		intel_modeset_init_hw(dev);
> -		intel_modeset_setup_hw_state(dev, false);
> +
> +		drm_modeset_lock_all(dev);
> +		intel_modeset_setup_hw_state(dev, true);
> +		drm_modeset_unlock_all(dev);
>   
>   		/*
>   		 * ... but also need to make sure that hotplug processing
> diff --git a/drivers/gpu/drm/i915/intel_fb.c b/drivers/gpu/drm/i915/intel_fb.c
> index f203418..8d81c929 100644
> --- a/drivers/gpu/drm/i915/intel_fb.c
> +++ b/drivers/gpu/drm/i915/intel_fb.c
> @@ -150,6 +150,9 @@ static int intelfb_create(struct drm_fb_helper *helper,
>   	}
>   	info->screen_size = size;
>   
> +	/* This driver doesn't need a VT switch to restore the mode on resume */
> +	info->skip_vt_switch = true;
> +
>   	drm_fb_helper_fill_fix(info, fb->pitches[0], fb->depth);
>   	drm_fb_helper_fill_var(info, &ifbdev->helper, sizes->fb_width, sizes->fb_height);
>   

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