drm/sched: add optional errno to drm_sched_start()

The current implementation of drm_sched_start uses a hardcoded
-ECANCELED to dispose of a job when the parent/hw fence is NULL.
This results in drm_sched_job_done being called with -ECANCELED for
each job with a NULL parent in the pending list, making it difficult
to distinguish between recovery methods, whether a queue reset or a
full GPU reset was used.

To improve this, we first try a soft recovery for timeout jobs and
use the error code -ENODATA. If soft recovery fails, we proceed with
a queue reset, where the error code remains -ENODATA for the job.
Finally, for a full GPU reset, we use error codes -ECANCELED or
-ETIME. This patch adds an error code parameter to drm_sched_start,
allowing us to differentiate between queue reset and GPU reset
failures. This enables user mode and test applications to validate
the expected correctness of the requested operation. After a
successful queue reset, the only way to continue normal operation is
to call drm_sched_job_done with the specific error code -ENODATA.

v1: Initial implementation by Jesse utilized amdgpu_device_lock_reset_domain
    and amdgpu_device_unlock_reset_domain to allow user mode to track
    the queue reset status and distinguish between queue reset and
    GPU reset.
v2: Christian suggested using the error codes -ENODATA for queue reset
    and -ECANCELED or -ETIME for GPU reset, returned to
    amdgpu_cs_wait_ioctl.
v3: To meet the requirements, we introduce a new function
    drm_sched_start_ex with an additional parameter to set
    dma_fence_set_error, allowing us to handle the specific error
    codes appropriately and dispose of bad jobs with the selected
    error code depending on whether it was a queue reset or GPU reset.
v4: Alex suggested using a new name, drm_sched_start_with_recovery_error,
    which more accurately describes the function's purpose.
    Additionally, it was recommended to add documentation details
    about the new method.
v5: Fixed declaration of new function drm_sched_start_with_recovery_error.(Alex)
v6 (chk): rebase on upstream changes, cleanup the commit message,
          drop the new function again and update all callers,
          apply the errno also to scheduler fences with hw fences
v7 (chk): rebased

Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240826122541.85663-1-christian.koenig@amd.com

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index ab53ab486fe6..f093616fe53c 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -674,9 +674,10 @@ EXPORT_SYMBOL(drm_sched_stop);
  * drm_sched_start - recover jobs after a reset
  *
  * @sched: scheduler instance
+ * @errno: error to set on the pending fences
  *
  */
-void drm_sched_start(struct drm_gpu_scheduler *sched)
+void drm_sched_start(struct drm_gpu_scheduler *sched, int errno)
 {
 	struct drm_sched_job *s_job, *tmp;
 
@@ -691,13 +692,13 @@ void drm_sched_start(struct drm_gpu_scheduler *sched)
 		atomic_add(s_job->credits, &sched->credit_count);
 
 		if (!fence) {
-			drm_sched_job_done(s_job, -ECANCELED);
+			drm_sched_job_done(s_job, errno ?: -ECANCELED);
 			continue;
 		}
 
 		if (dma_fence_add_callback(fence, &s_job->cb,
 					   drm_sched_job_done_cb))
-			drm_sched_job_done(s_job, fence->error);
+			drm_sched_job_done(s_job, fence->error ?: errno);
 	}
 
 	drm_sched_start_timeout_unlocked(sched);