drm/amdgpu: don't reemit if there is nothing to reemit

Return early in amdgpu_ring_set_fence_errors_and_reemit()
if ring_backup_entries_to_copy is 0.  That means that either
the ring is idle and there is nothing to reemit, or there
some reason why we should reemit, so return early and
signal the fences (if applicable).

Reviewed-by: Jesse Zhang <jesse.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
index ea69b1bac7c6..6a43c8494fa8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -727,6 +727,15 @@ void amdgpu_ring_set_fence_errors_and_reemit(struct amdgpu_ring *ring,
 	last_seq = amdgpu_fence_read(ring) & ring->fence_drv.num_fences_mask;
 	seq = ring->fence_drv.sync_seq & ring->fence_drv.num_fences_mask;
 
+	/* If there is nothing to reemit, return early and set an error on the fence
+	 * if applicable. If all of the fences are siganlled, this will be a nop.
+	 * if there are still fences and ring_backup_entries_to_copy is 0, then
+	 * we are skipping it on purpose.
+	 */
+	if (!ring->ring_backup_entries_to_copy) {
+		amdgpu_fence_driver_force_completion(ring, &guilty_fence->base);
+		return;
+	}
 	ring->reemit = true;
 	amdgpu_ring_alloc(ring, ring->ring_backup_entries_to_copy);
 	spin_lock_irqsave(&ring->fence_drv.lock, flags);