[Intel-gfx] [PATCH] drm/i915: Disable primary plane if we fail to reconstruct BIOS fb

[Chris Wilson]

On Mon, Nov 23, 2015 at 04:10:58PM -0800, Matt Roper wrote:
> On Mon, Nov 23, 2015 at 04:53:55PM +0000, Chris Wilson wrote:
> > On Mon, Nov 23, 2015 at 08:48:32AM -0800, Matt Roper wrote:
> > > If we fail to reconstruct the BIOS fb (e.g., because the FB is too
> > > large), we'll be left with plane state that indicates the primary plane
> > > is visible yet has a NULL fb.  This mismatch causes problems later on
> > > (e.g., for the watermark code).  Since we've failed to reconstruct the
> > > BIOS FB, the best solution is to just disable the primary plane and
> > > pretend the BIOS never had it enabled.
> > > 
> > > Cc: Daniel Vetter <daniel at ffwll.ch>
> > > Cc: Ville Syrjälä <ville.syrjala at intel.com>
> > > Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
> > 
> > There are a bunch of bugzillas open about this as it is a regression
> > from about 3.2.
> > -Chris
> > 
> 
> Do you happen to know any of the bug ID's off the top of your head (or
> keywords to look for)?  I skimmed through the bug list, but the only one
> that jumped out at me as possibly related is
> 
> https://bugs.freedesktop.org/show_bug.cgi?id=91751
> ("Display still active even though primary plane is disabled and kills
> the GPU")

Errors like https://bugs.freedesktop.org/show_bug.cgi?id=89319 or GPU
hangs on takeover like
https://bugs.freedesktop.org/show_bug.cgi?id=87677
https://bugs.freedesktop.org/show_bug.cgi?id=89146
https://bugs.freedesktop.org/show_bug.cgi?id=91653
from a quick search
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre