Commit 9d56cbaf authored by Philipp Stanner's avatar Philipp Stanner
Browse files

drm/todo: Add section with task for GPU scheduler 



The GPU scheduler has a great many problems and deserves its own TODO
section.

Add a section and a first task describing the problem of
drm_sched_resubmit_jobs() being deprecated without a successor.

Acked-by: default avatarDave Airlie <airlied@redhat.com>
Signed-off-by: default avatarPhilipp Stanner <phasta@kernel.org>
Link: https://patch.msgid.link/20251107135701.244659-3-phasta@kernel.org
parent 7068d420

Documentation/gpu/todo.rst

+31 −0
Original line number Diff line number Diff line
@@ -878,6 +878,37 @@ Contact: Christian König 


Level: Starter



DRM GPU Scheduler

=================



Provide a universal successor for drm_sched_resubmit_jobs()

-----------------------------------------------------------



drm_sched_resubmit_jobs() is deprecated. Main reason being that it leads to

reinitializing dma_fences. See that function's docu for details. The better

approach for valid resubmissions by amdgpu and Xe is (apparently) to figure out

which job (and, through association: which entity) caused the hang. Then, the

job's buffer data, together with all other jobs' buffer data currently in the

same hardware ring, must be invalidated. This can for example be done by

overwriting it. amdgpu currently determines which jobs are in the ring and need

to be overwritten by keeping copies of the job. Xe obtains that information by

directly accessing drm_sched's pending_list.



Tasks:



1. implement scheduler functionality through which the driver can obtain the

   information which *broken* jobs are currently in the hardware ring.

2. Such infrastructure would then typically be used in

   drm_sched_backend_ops.timedout_job(). Document that.

3. Port a driver as first user.

4. Document the new alternative in the docu of deprecated

   drm_sched_resubmit_jobs().



Contact: Christian König <christian.koenig@amd.com>

         Philipp Stanner <phasta@kernel.org>



Level: Advanced



Outside DRM

===========