On Thu, Mar 09, 2023 at 12:09:55PM +0100, Maarten Lankhorst wrote: > > On 2023-03-09 12:04, Hogander, Jouni wrote: > > 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? > > No other driver does that. Every driver does that when you run X w/o a compositor. Assuming there is an actual GPU in there. > It's fine if DirtyFB hangs instead until the > job it waits on completes. No one tried to make it just wait for the fence(s) w/o doing a full blown atomic commit. It might work, but might also still suck too much. I guess depends on how overloaded the GPU is. What we could do is do a frontbuffer invalidate on dirtyfb invocation, and then once the fence(s) signal we do a frontbuffer flush. That would most closely match the gem hook behaviour, except the invalidate comes in a bit later. The alternative would be to skip the invalidate, which should still guarantee correctness in the end, just with possibly jankier interactivity. -- Ville Syrjälä Intel
