FAILED: patch "[PATCH] drm/vmwgfx: Also check for crtc status while checking for DU" failed to apply to 4.20-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 4.20-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 <stable@xxxxxxxxxxxxxxx>.

thanks,

greg k-h

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

>From 479d59026fe44f89fa67efa01a4d47e00808e688 Mon Sep 17 00:00:00 2001
From: Deepak Rawat <drawat@xxxxxxxxxx>
Date: Fri, 21 Dec 2018 14:38:35 -0800
Subject: [PATCH] drm/vmwgfx: Also check for crtc status while checking for DU
 active

During modeset check it is possible to have all crtc_state's in atomic
state. Check for crtc enable status while checking for display unit
active status. Only error if enabling a crtc while display unit is not
active.

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 9da6e26c0aae: ("drm/vmwgfx: Fix a layout race condition")
Signed-off-by: Deepak Rawat <drawat@xxxxxxxxxx>
Reviewed-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 5e257a600cea..ed2f67822f45 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -1646,7 +1646,7 @@ static int vmw_kms_check_topology(struct drm_device *dev,
 		struct drm_connector_state *conn_state;
 		struct vmw_connector_state *vmw_conn_state;
 
-		if (!du->pref_active) {
+		if (!du->pref_active && new_crtc_state->enable) {
 			ret = -EINVAL;
 			goto clean;
 		}