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authorBoris Brezillon <boris.brezillon@collabora.com>2021-06-30 09:27:36 +0300
committerBoris Brezillon <boris.brezillon@collabora.com>2021-07-01 09:53:25 +0300
commit1fad1b7ed1ebfcfb5a1d0d21b0c47f7af5f49a6c (patch)
treeb437d7a2d9539a8dabf7afea226088fbbb7170b4 /include
parent60f3c604bcc0c13f3fbbf75a4c7be87134023a3c (diff)
downloadlinux-1fad1b7ed1ebfcfb5a1d0d21b0c47f7af5f49a6c.tar.xz
drm/sched: Document what the timedout_job method should do
The documentation is a bit vague and doesn't really describe what the ->timedout_job() is expected to do. Let's add a few more details. v5: * New patch Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210630062751.2832545-2-boris.brezillon@collabora.com
Diffstat (limited to 'include')
-rw-r--r--include/drm/gpu_scheduler.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index d18af49fd009..aa90ed1f1b2b 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -239,6 +239,20 @@ struct drm_sched_backend_ops {
* @timedout_job: Called when a job has taken too long to execute,
* to trigger GPU recovery.
*
+ * This method is called in a workqueue context.
+ *
+ * Drivers typically issue a reset to recover from GPU hangs, and this
+ * procedure usually follows the following workflow:
+ *
+ * 1. Stop the scheduler using drm_sched_stop(). This will park the
+ * scheduler thread and cancel the timeout work, guaranteeing that
+ * nothing is queued while we reset the hardware queue
+ * 2. Try to gracefully stop non-faulty jobs (optional)
+ * 3. Issue a GPU reset (driver-specific)
+ * 4. Re-submit jobs using drm_sched_resubmit_jobs()
+ * 5. Restart the scheduler using drm_sched_start(). At that point, new
+ * jobs can be queued, and the scheduler thread is unblocked
+ *
* Return DRM_GPU_SCHED_STAT_NOMINAL, when all is normal,
* and the underlying driver has started or completed recovery.
*