drm/tegra: Annotate dma-fence critical section in commit path

Again ends just after drm_atomic_helper_commit_hw_done(), but with the
twist that we need to make sure we're only annotate the custom
version. And not the other clause which just calls
drm_atomic_helper_commit_tail_rpm(), which is already annotated.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-tegra@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20210121152959.1725404-11-daniel.vetter@ffwll.ch

drivers/gpu/drm/tegra/drm.c

@@ -65,11 +65,14 @@ static void tegra_atomic_commit_tail(struct drm_atomic_state *old_state)
 	struct tegra_drm *tegra = drm->dev_private;
 
 	if (tegra->hub) {
+		bool fence_cookie = dma_fence_begin_signalling();
+
 		drm_atomic_helper_commit_modeset_disables(drm, old_state);
 		tegra_display_hub_atomic_commit(drm, old_state);
 		drm_atomic_helper_commit_planes(drm, old_state, 0);
 		drm_atomic_helper_commit_modeset_enables(drm, old_state);
 		drm_atomic_helper_commit_hw_done(old_state);
+		dma_fence_end_signalling(fence_cookie);
 		drm_atomic_helper_wait_for_vblanks(drm, old_state);
 		drm_atomic_helper_cleanup_planes(drm, old_state);
 	} else {