drm/sched: Set error to s_fence if HW job submission failed.

Problem:
When run_job fails and HW fence returned is NULL we still signal
the s_fence to avoid hangs but the user has no way of knowing if
the actual HW job was ran and finished.

Fix:
Allow .run_job implementations to return ERR_PTR in the fence pointer
returned and then set this error for s_fence->finished fence so whoever
wait on this fence can inspect the signaled fence for an error.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 9a0ee74d82dc..f39b97ed4ade 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -479,6 +479,7 @@ void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
         struct drm_sched_job *s_job, *tmp;
         uint64_t guilty_context;
         bool found_guilty = false;
+        struct dma_fence *fence;
 
         list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
                 struct drm_sched_fence *s_fence = s_job->s_fence;
@@ -492,7 +493,16 @@ void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
                         dma_fence_set_error(&s_fence->finished, -ECANCELED);
 
                 dma_fence_put(s_job->s_fence->parent);
-                s_job->s_fence->parent = sched->ops->run_job(s_job);
+                fence = sched->ops->run_job(s_job);
+
+                if (IS_ERR_OR_NULL(fence)) {
+                        s_job->s_fence->parent = NULL;
+                        dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
+                } else {
+                        s_job->s_fence->parent = fence;
+                }
+
+
         }
 }
 EXPORT_SYMBOL(drm_sched_resubmit_jobs);
@@ -720,7 +730,7 @@ static int drm_sched_main(void *param)
                 fence = sched->ops->run_job(sched_job);
                 drm_sched_fence_scheduled(s_fence);
 
-                if (fence) {
+                if (!IS_ERR_OR_NULL(fence)) {
                         s_fence->parent = dma_fence_get(fence);
                         r = dma_fence_add_callback(fence, &sched_job->cb,
                                                    drm_sched_process_job);
@@ -730,8 +740,11 @@ static int drm_sched_main(void *param)
                                 DRM_ERROR("fence add callback failed (%d)\n",
                                           r);
                         dma_fence_put(fence);
-                } else
+                } else {
+
+                        dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
                         drm_sched_process_job(NULL, &sched_job->cb);
+                }
 
                 wake_up(&sched->job_scheduled);
         }