[PATCH v2 23/23] drm/sched: Add (optional) fence signaling annotation

[Rob Clark <robdclark@gmail.com>]

From: Rob Clark <robdclark@chromium.org>

Based on
https://lore.kernel.org/dri-devel/20200604081224.863494-10-daniel.vetter@ffwll.ch/
but made to be optional.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/msm/msm_ringbuffer.c   | 1 +
 drivers/gpu/drm/scheduler/sched_main.c | 9 +++++++++
 include/drm/gpu_scheduler.h            | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.c b/drivers/gpu/drm/msm/msm_ringbuffer.c
index b60199184409..7e42baf16cd0 100644
--- a/drivers/gpu/drm/msm/msm_ringbuffer.c
+++ b/drivers/gpu/drm/msm/msm_ringbuffer.c
@@ -93,6 +93,7 @@ struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
 	 /* currently managing hangcheck ourselves: */
 	sched_timeout = MAX_SCHEDULE_TIMEOUT;
 
+	ring->sched.fence_signaling = true;
 	ret = drm_sched_init(&ring->sched, &msm_sched_ops,
 			num_hw_submissions, 0, sched_timeout,
 			NULL, NULL, to_msm_bo(ring->bo)->name, gpu->dev->dev);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 4e6ad6e122bc..c2ee44d6224b 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -978,10 +978,15 @@ static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
 static int drm_sched_main(void *param)
 {
 	struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
+	const bool fence_signaling = sched->fence_signaling;
+	bool fence_cookie;
 	int r;
 
 	sched_set_fifo_low(current);
 
+	if (fence_signaling)
+		fence_cookie = dma_fence_begin_signalling();
+
 	while (!kthread_should_stop()) {
 		struct drm_sched_entity *entity = NULL;
 		struct drm_sched_fence *s_fence;
@@ -1039,6 +1044,10 @@ static int drm_sched_main(void *param)
 
 		wake_up(&sched->job_scheduled);
 	}
+
+	if (fence_signaling)
+		dma_fence_end_signalling(fence_cookie);
+
 	return 0;
 }
 
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 9db9e5e504ee..8f23ea522e22 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -483,6 +483,7 @@ struct drm_sched_backend_ops {
  * @ready: marks if the underlying HW is ready to work
  * @free_guilty: A hit to time out handler to free the guilty job.
  * @dev: system &struct device
+ * @fence_signaling: Opt in to fence signaling annotations
  *
  * One scheduler is implemented for each hardware ring.
  */
@@ -507,6 +508,7 @@ struct drm_gpu_scheduler {
 	bool				ready;
 	bool				free_guilty;
 	struct device			*dev;
+	bool 				fence_signaling;
 };
 
 int drm_sched_init(struct drm_gpu_scheduler *sched,
-- 
2.39.2