[Intel-gfx] [PATCH v2] drm/i915: Don't clobber crtc->fb when queue_flip fails

[Ville Syrjälä]

On Sun, Mar 03, 2013 at 07:52:33PM +0100, Daniel Vetter wrote:
> On Fri, Feb 22, 2013 at 03:13:00PM +0000, Chris Wilson wrote:
> > On Fri, Feb 22, 2013 at 04:53:38PM +0200, ville.syrjala at linux.intel.com wrote:
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > 
> > > Restore crtc->fb to the old framebuffer if queue_flip fails.
> > > 
> > > While at it, kill the pointless intel_fb temp variable.
> > > 
> > > v2: Update crtc->fb before queue_flip and restore it back
> > >     after a failure.
> > > 
> > > Cc: stable at vger.kernel.org
> > > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > Lgtm, either v1 or v2 gets my
> > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> > (with a slight preference towards v2 for the sake of paranoia)
> 
> Picked up for -fixes, thanks for the patch. And can I wish for an i-g-t
> for this?

Hmm. I think it's a bit difficult to hit it systematically due to a
GPU reset. We need to call queue_flip after a hang was detected but
before the reset work has a chance to run.

But after a bit more though we should hit the same bug by trying to
flip to a Y-tiled buffer. I'll try to make a test based on that.

-- 
Ville Syrjälä
Intel OTC