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

[Souza, Jose]

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.

>