commit f7fe64ad0f22 ("drm/sched: Split free_job into own work item")
causes graphics hangs at GDM or right after logging in on a
Framework 13 AMD laptop (containing a Phoenix APU).

This reverts commit f7fe64ad0f22ff034f8ebcfbd7299ee9cc9b57d7.

Fixes: f7fe64ad0f22 ("drm/sched: Split free_job into own work item")
Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
---
This is a regression introduced in 6.8-rc1, bisected from 6.7.
This revert done on top of 6.8-rc1 fixes the issue.

I'm happy to gather any data to use to properly debug if that is
preferable to a revert.
---
 drivers/gpu/drm/scheduler/sched_main.c | 133 +++++++++----------------
 include/drm/gpu_scheduler.h            |   4 +-
 2 files changed, 48 insertions(+), 89 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c 
b/drivers/gpu/drm/scheduler/sched_main.c
index 550492a7a031..91c96ab53fb5 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -369,32 +369,6 @@ static void drm_sched_run_job_queue(struct 
drm_gpu_scheduler *sched)
                queue_work(sched->submit_wq, &sched->work_run_job);
 }
 
-/**
- * __drm_sched_run_free_queue - enqueue free-job work
- * @sched: scheduler instance
- */
-static void __drm_sched_run_free_queue(struct drm_gpu_scheduler *sched)
-{
-       if (!READ_ONCE(sched->pause_submit))
-               queue_work(sched->submit_wq, &sched->work_free_job);
-}
-
-/**
- * drm_sched_run_free_queue - enqueue free-job work if ready
- * @sched: scheduler instance
- */
-static void drm_sched_run_free_queue(struct drm_gpu_scheduler *sched)
-{
-       struct drm_sched_job *job;
-
-       spin_lock(&sched->job_list_lock);
-       job = list_first_entry_or_null(&sched->pending_list,
-                                      struct drm_sched_job, list);
-       if (job && dma_fence_is_signaled(&job->s_fence->finished))
-               __drm_sched_run_free_queue(sched);
-       spin_unlock(&sched->job_list_lock);
-}
-
 /**
  * drm_sched_job_done - complete a job
  * @s_job: pointer to the job which is done
@@ -414,7 +388,7 @@ static void drm_sched_job_done(struct drm_sched_job *s_job, 
int result)
        dma_fence_get(&s_fence->finished);
        drm_sched_fence_finished(s_fence, result);
        dma_fence_put(&s_fence->finished);
-       __drm_sched_run_free_queue(sched);
+       drm_sched_run_job_queue(sched);
 }
 
 /**
@@ -1092,10 +1066,8 @@ drm_sched_get_finished_job(struct drm_gpu_scheduler 
*sched)
                                                typeof(*next), list);
 
                if (next) {
-                       if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT,
-                                    &next->s_fence->scheduled.flags))
-                               next->s_fence->scheduled.timestamp =
-                                       
dma_fence_timestamp(&job->s_fence->finished);
+                       next->s_fence->scheduled.timestamp =
+                               dma_fence_timestamp(&job->s_fence->finished);
                        /* start TO timer for next job */
                        drm_sched_start_timeout(sched);
                }
@@ -1145,29 +1117,7 @@ drm_sched_pick_best(struct drm_gpu_scheduler 
**sched_list,
 EXPORT_SYMBOL(drm_sched_pick_best);
 
 /**
- * drm_sched_free_job_work - worker to call free_job
- *
- * @w: free job work
- */
-static void drm_sched_free_job_work(struct work_struct *w)
-{
-       struct drm_gpu_scheduler *sched =
-               container_of(w, struct drm_gpu_scheduler, work_free_job);
-       struct drm_sched_job *job;
-
-       if (READ_ONCE(sched->pause_submit))
-               return;
-
-       job = drm_sched_get_finished_job(sched);
-       if (job)
-               sched->ops->free_job(job);
-
-       drm_sched_run_free_queue(sched);
-       drm_sched_run_job_queue(sched);
-}
-
-/**
- * drm_sched_run_job_work - worker to call run_job
+ * drm_sched_run_job_work - main scheduler thread
  *
  * @w: run job work
  */
@@ -1176,50 +1126,64 @@ static void drm_sched_run_job_work(struct work_struct 
*w)
        struct drm_gpu_scheduler *sched =
                container_of(w, struct drm_gpu_scheduler, work_run_job);
        struct drm_sched_entity *entity;
-       struct dma_fence *fence;
-       struct drm_sched_fence *s_fence;
-       struct drm_sched_job *sched_job;
+       struct drm_sched_job *cleanup_job;
        int r;
 
        if (READ_ONCE(sched->pause_submit))
                return;
 
+       cleanup_job = drm_sched_get_finished_job(sched);
        entity = drm_sched_select_entity(sched);
-       if (!entity)
-               return;
 
-       sched_job = drm_sched_entity_pop_job(entity);
-       if (!sched_job) {
-               complete_all(&entity->entity_idle);
+       if (!entity && !cleanup_job)
                return; /* No more work */
-       }
 
-       s_fence = sched_job->s_fence;
+       if (cleanup_job)
+               sched->ops->free_job(cleanup_job);
 
-       atomic_add(sched_job->credits, &sched->credit_count);
-       drm_sched_job_begin(sched_job);
+       if (entity) {
+               struct dma_fence *fence;
+               struct drm_sched_fence *s_fence;
+               struct drm_sched_job *sched_job;
+
+               sched_job = drm_sched_entity_pop_job(entity);
+               if (!sched_job) {
+                       complete_all(&entity->entity_idle);
+                       if (!cleanup_job)
+                               return; /* No more work */
+                       goto again;
+               }
 
-       trace_drm_run_job(sched_job, entity);
-       fence = sched->ops->run_job(sched_job);
-       complete_all(&entity->entity_idle);
-       drm_sched_fence_scheduled(s_fence, fence);
+               s_fence = sched_job->s_fence;
 
-       if (!IS_ERR_OR_NULL(fence)) {
-               /* Drop for original kref_init of the fence */
-               dma_fence_put(fence);
+               atomic_inc(&sched->credit_count);
+               drm_sched_job_begin(sched_job);
 
-               r = dma_fence_add_callback(fence, &sched_job->cb,
-                                          drm_sched_job_done_cb);
-               if (r == -ENOENT)
-                       drm_sched_job_done(sched_job, fence->error);
-               else if (r)
-                       DRM_DEV_ERROR(sched->dev, "fence add callback failed 
(%d)\n", r);
-       } else {
-               drm_sched_job_done(sched_job, IS_ERR(fence) ?
-                                  PTR_ERR(fence) : 0);
+               trace_drm_run_job(sched_job, entity);
+               fence = sched->ops->run_job(sched_job);
+               complete_all(&entity->entity_idle);
+               drm_sched_fence_scheduled(s_fence, fence);
+
+               if (!IS_ERR_OR_NULL(fence)) {
+                       /* Drop for original kref_init of the fence */
+                       dma_fence_put(fence);
+
+                       r = dma_fence_add_callback(fence, &sched_job->cb,
+                                                  drm_sched_job_done_cb);
+                       if (r == -ENOENT)
+                               drm_sched_job_done(sched_job, fence->error);
+                       else if (r)
+                               DRM_DEV_ERROR(sched->dev, "fence add callback 
failed (%d)\n",
+                                         r);
+               } else {
+                       drm_sched_job_done(sched_job, IS_ERR(fence) ?
+                                          PTR_ERR(fence) : 0);
+               }
+
+               wake_up(&sched->job_scheduled);
        }
 
-       wake_up(&sched->job_scheduled);
+again:
        drm_sched_run_job_queue(sched);
 }
 
@@ -1304,7 +1268,6 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
        atomic_set(&sched->credit_count, 0);
        INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
        INIT_WORK(&sched->work_run_job, drm_sched_run_job_work);
-       INIT_WORK(&sched->work_free_job, drm_sched_free_job_work);
        atomic_set(&sched->_score, 0);
        atomic64_set(&sched->job_id_count, 0);
        sched->pause_submit = false;
@@ -1432,7 +1395,6 @@ void drm_sched_wqueue_stop(struct drm_gpu_scheduler 
*sched)
 {
        WRITE_ONCE(sched->pause_submit, true);
        cancel_work_sync(&sched->work_run_job);
-       cancel_work_sync(&sched->work_free_job);
 }
 EXPORT_SYMBOL(drm_sched_wqueue_stop);
 
@@ -1445,6 +1407,5 @@ void drm_sched_wqueue_start(struct drm_gpu_scheduler 
*sched)
 {
        WRITE_ONCE(sched->pause_submit, false);
        queue_work(sched->submit_wq, &sched->work_run_job);
-       queue_work(sched->submit_wq, &sched->work_free_job);
 }
 EXPORT_SYMBOL(drm_sched_wqueue_start);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 5acc64954a88..72f64bd0a6eb 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -495,10 +495,9 @@ struct drm_sched_backend_ops {
  *                 waits on this wait queue until all the scheduled jobs are
  *                 finished.
  * @job_id_count: used to assign unique id to the each job.
- * @submit_wq: workqueue used to queue @work_run_job and @work_free_job
+ * @submit_wq: workqueue used to queue @work_run_job
  * @timeout_wq: workqueue used to queue @work_tdr
  * @work_run_job: work which calls run_job op of each scheduler.
- * @work_free_job: work which calls free_job op of each scheduler.
  * @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the
  *            timeout interval is over.
  * @pending_list: the list of jobs which are currently in the job queue.
@@ -528,7 +527,6 @@ struct drm_gpu_scheduler {
        struct workqueue_struct         *submit_wq;
        struct workqueue_struct         *timeout_wq;
        struct work_struct              work_run_job;
-       struct work_struct              work_free_job;
        struct delayed_work             work_tdr;
        struct list_head                pending_list;
        spinlock_t                      job_list_lock;
-- 
2.34.1

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