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

["Hogander, Jouni" <jouni.hogander@intel.com>]

On Mon, 2023-03-06 at 22:58 +0200, 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.
> 

CRC calculation doesn't work with PSR currently. PSR is disabled if CRC
capture is requested.

Are we supposed to support frontbuffer rendering using GPU?

BR,

Jouni Högander