Am 08.07.21 um 19:37 schrieb Daniel Vetter:
If it does, someone managed to set up a sched_entity without
schedulers, which is just a driver bug.
NAK, it is perfectly valid for rq selection to fail.
See drm_sched_pick_best():
if (!sched->ready) {
DRM_WARN("scheduler %s is not ready, skipping",
sched->name);
continue;
}
This can happen when a device reset fails for some engine.
Regards,
Christian.
We BUG_ON() here because in the next patch drm_sched_job_init() will
be split up, with drm_sched_job_arm() never failing. And that's the
part where the rq selection will end up in.
Note that if having an empty sched_list set on an entity is indeed a
valid use-case, we can keep that check in job_init even after the split
into job_init/arm.
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: "Christian König" <christian.koenig@xxxxxxx>
Cc: Luben Tuikov <luben.tuikov@xxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Steven Price <steven.price@xxxxxxx>
Cc: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Cc: Jack Zhang <Jack.Zhang1@xxxxxxx>
---
drivers/gpu/drm/scheduler/sched_entity.c | 2 +-
drivers/gpu/drm/scheduler/sched_main.c | 3 +--
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 79554aa4dbb1..6fc116ee7302 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -45,7 +45,7 @@
* @guilty: atomic_t set to 1 when a job on this queue
* is found to be guilty causing a timeout
*
- * Note: the sched_list should have at least one element to schedule
+ * Note: the sched_list must have at least one element to schedule
* the entity
*
* Returns 0 on success or a negative error code on failure.
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 33c414d55fab..01dd47154181 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -586,8 +586,7 @@ int drm_sched_job_init(struct drm_sched_job *job,
struct drm_gpu_scheduler *sched;
drm_sched_entity_select_rq(entity);
- if (!entity->rq)
- return -ENOENT;
+ BUG_ON(!entity->rq);
sched = entity->rq->sched;
