Re: [PATCH 02/10] drm/i915: Decouple the stuck pageflip on modeset

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Sep 02, 2014 at 02:57:37PM +0100, Chris Wilson wrote:
> If we successfully confuse the hardware, and cause it to drop a queued
> pageflip, we wait for 60s and issue a warning before continuing on with
> the modeset. However, this leaves the pending pageflip still stuck
> indefinitely. Pretend to userspace that it does complete, and let us
> start afresh following the modeset.
> 
> v2: Rebase after refactor
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Yeah, seems better than having the flip stuck forever.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/intel_display.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 18c431e4f099..bbc3d509bcd7 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3434,9 +3434,19 @@ void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
>  	WARN_ON(waitqueue_active(&dev_priv->pending_flip_queue));
> -	WARN_ON(wait_event_timeout(dev_priv->pending_flip_queue,
> -				   !intel_crtc_has_pending_flip(crtc),
> -				   60*HZ) == 0);
> +	if (WARN_ON(wait_event_timeout(dev_priv->pending_flip_queue,
> +				       !intel_crtc_has_pending_flip(crtc),
> +				       60*HZ) == 0)) {
> +		struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +		unsigned long flags;
> +
> +		spin_lock_irqsave(&dev->event_lock, flags);
> +		if (intel_crtc->unpin_work) {
> +			WARN_ONCE(1, "Removing stuck page flip\n");
> +			page_flip_completed(intel_crtc);
> +		}
> +		spin_unlock_irqrestore(&dev->event_lock, flags);
> +	}
>  
>  	if (crtc->primary->fb) {
>  		mutex_lock(&dev->struct_mutex);
> -- 
> 2.1.0

-- 
Ville Syrjälä
Intel OTC