Re: [Intel-gfx] [Intel-xe] [PATCH] drm/xe/display: Do not use i915 frontbuffer tracking implementation

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

On Wed, Mar 08, 2023 at 01:47:12PM +0100, Maarten Lankhorst wrote:
> 
> On 2023-03-06 21:58, Ville Syrjälä wrote:
> > On Mon, Mar 06, 2023 at 09:23:50PM +0100, Maarten Lankhorst wrote:
> >> Hey,
> >>
> >> On 2023-03-06 16:23, Souza, Jose wrote:
> >>> On Mon, 2023-03-06 at 15:16 +0100, Maarten Lankhorst wrote:
> >>>> As a fallback if we decide not to merge the frontbuffer tracking, allow
> >>>> i915 to keep its own implementation, and do the right thing in Xe.
> >>>>
> >>>> The frontbuffer tracking for Xe is still done per-fb, while i915 can
> >>>> keep doing the weird intel_frontbuffer + i915_active thing without
> >>>> blocking Xe.
> >>> Please also disable PSR and FBC with this or at least add a way for users to disable those features.
> >>> Without frontbuffer tracker those two features will break in some cases.
> >> FBC and PSR work completely as expected. I don't remove frontbuffer
> >> tracking; I only remove the GEM parts.
> >>
> >> Explicit invalidation using pageflip or CPU rendering + DirtyFB continue
> >> to work, as I validated on my laptop with FBC.
> > Neither of which are relevant to the removal of the gem hooks.
> >
> > Like I already said ~10 times in the last meeting, we need a proper
> > testcase. Here's a rough idea what it should do:
> >
> > prepare a batch with
> > 1. spinner
> > 2. something that clobbers the fb
> >
> > Then
> > 1. grab reference crc
> > 2. execbuffer
> > 3. dirtyfb
> > 4. wait long enough for fbc to recompress
> > 5. terminate spinner
> > 6. gem_sync
> > 7. grab crc and compare with reference
> >
> > No idea what the current status of PSR+CRC is, so not sure
> > whether we can actually test PSR or not.
> 
> This test doesn't make sense. DirtyFB should simply not return before 
> execbuffer finishes.

Of course it should. It's not a blocking ioctl, and can't
be because that will make X unusable.

-- 
Ville Syrjälä
Intel