drm/amd/display: wait for fence without holding reservation lock

Don't block others while waiting for the fences to finish, concurrent
submission is perfectly valid in this case and holding the lock can
prevent killed applications from terminating.
Signed-off-by: Christian König <ckoenig.leichtzumerken@gmail.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -5205,23 +5205,26 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
 			continue;
 		}
 
+		abo = gem_to_amdgpu_bo(fb->obj[0]);
+
+		/* Wait for all fences on this FB */
+		r = reservation_object_wait_timeout_rcu(abo->tbo.resv, true,
+							false,
+							MAX_SCHEDULE_TIMEOUT);
+		WARN_ON(r < 0);
+
 		/*
 		 * TODO This might fail and hence better not used, wait
 		 * explicitly on fences instead
 		 * and in general should be called for
 		 * blocking commit to as per framework helpers
 		 */
-		abo = gem_to_amdgpu_bo(fb->obj[0]);
 		r = amdgpu_bo_reserve(abo, true);
 		if (unlikely(r != 0)) {
 			DRM_ERROR("failed to reserve buffer before flip\n");
 			WARN_ON(1);
 		}
 
-		/* Wait for all fences on this FB */
-		WARN_ON(reservation_object_wait_timeout_rcu(abo->tbo.resv, true, false,
-									    MAX_SCHEDULE_TIMEOUT) < 0);
-
 		amdgpu_bo_get_tiling_flags(abo, &tiling_flags);
 
 		amdgpu_bo_unreserve(abo);