linux-kernel - [PATCH v2 3/4] drm/sched: Add TODO entry for resubmitting jobs

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Message-ID: <20251023143031.149496-5-phasta@kernel.org>
Date: Thu, 23 Oct 2025 16:30:30 +0200
From: Philipp Stanner <phasta@...nel.org>
To: Matthew Brost <matthew.brost@...el.com>,
	Danilo Krummrich <dakr@...nel.org>,
	Philipp Stanner <phasta@...nel.org>,
	Christian König <ckoenig.leichtzumerken@...il.com>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Tvrtko Ursulin <tvrtko.ursulin@...lia.com>
Cc: dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org
Subject: [PATCH v2 3/4] drm/sched: Add TODO entry for resubmitting jobs

Add the issue of a successor of drm_sched_resubmit_jobs() missing to the
TODO file.

Signed-off-by: Philipp Stanner <phasta@...nel.org>
---
 drivers/gpu/drm/scheduler/TODO | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/scheduler/TODO b/drivers/gpu/drm/scheduler/TODO
index 79044adb7d01..713dd62c58da 100644
--- a/drivers/gpu/drm/scheduler/TODO
+++ b/drivers/gpu/drm/scheduler/TODO
@@ -10,3 +10,29 @@
   - Tasks:
 	1. Read the example entry.
 	2. Remove the entry once solved (never in this case)
+
+* GPU job resubmits
+  - Difficulty: hard
+  - Contact:
+    - Christian König <ckoenig.leichtzumerken@...il.com>
+    - Philipp Stanner <phasta@...nel.org>
+  - Description:
+    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.
+	3. Document the new alternative in the docu of deprecated
+	   drm_sched_resubmit_jobs().
-- 
2.49.0