FAILED: patch "[PATCH] drm/atomic: Check old_plane_state->crtc in" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Boris Brezillon <[email protected]>
Date: Tue, 24 Jul 2018 15:32:15 +0200
Subject: [PATCH] drm/atomic: Check old_plane_state->crtc in
drm_atomic_helper_async_check()

Async plane update is supposed to work only when updating the FB or FB position of an already enabled plane. That does not apply to requests where the plane was previously disabled or assigned to a different CTRC.

Check old_plane_state->crtc value to make sure async plane update is allowed.

index 130da5195f3b..ff858b890045 100644
@@ -1527,7 +1527,8 @@ int drm_atomic_helper_async_check(struct drm_device *dev,
 	if (n_planes != 1)
 		return -EINVAL;
 
-	if (!new_plane_state->crtc)
+	if (!new_plane_state->crtc ||
+	    old_plane_state->crtc != new_plane_state->crtc)
 		return -EINVAL;
 
 	funcs = plane->helper_private;