[Intel-gfx] [PATCH 7/8] drm/i915/display/skl+: Drop frontbuffer rendering support

[Souza, Jose]

On Thu, 2021-08-19 at 19:07 +0300, Ville Syrjälä wrote:
> On Wed, Aug 18, 2021 at 07:48:03PM +0000, Souza, Jose wrote:
> > On Wed, 2021-08-18 at 17:55 +0300, Ville Syrjälä wrote:
> > > On Tue, Aug 17, 2021 at 05:42:15PM -0700, José Roberto de Souza wrote:
> > > > By now all the userspace applications should have migrated to atomic
> > > > or at least be calling DRM_IOCTL_MODE_DIRTYFB.
> > > > 
> > > > With that we can kill frontbuffer rendering support in i915 for
> > > > modern platforms.
> > > > 
> > > > So here converting legacy APIs into atomic commits so it can be
> > > > properly handled by driver i915.
> > > > 
> > > > Several IGT tests will fail with this changes, because some tests
> > > > were stressing those frontbuffer rendering scenarios that no userspace
> > > > should be using by now, fixes to IGT should be sent soon.
> > > 
> > > Blocking atomic commits instead of the current lightweight frontbuffer
> > > interface sounds like a terrible plan. How unusable is X with this
> > > approach?
> > 
> > 100% usable, had no issues when running X in TGL and ADL-P.
> > Added a debug message in intel_user_framebuffer_dirty() and X is not even using frontbuffer rendering at all.
> 
> Turn off your compositor if you want to test front buffer rendering.

Worked fine on Plasma with a 4K panel, was not able to find how to do that in Gnome.


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