[PATCH] drm: Only take cursor locks when the cursor plane exists

[Daniel Vetter]

I thought I've fixed this, but maybe not. Anyway, clearly broken, and
easy fix.

Cc: Tony Lindgren <tony at atomide.com>
Reported-by: Tony Lindgren <tony at atomide.com>
Fixes: b95ff0319a82 ("drm: Remove drm_modeset_(un)lock_crtc")
Cc: Harry Wentland <harry.wentland at amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Sean Paul <seanpaul at chromium.org>
Cc: David Airlie <airlied at linux.ie>
Cc: dri-devel at lists.freedesktop.org
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_plane.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 838ca742a28b..fedd4d60d9cd 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -720,15 +720,15 @@ static int drm_mode_cursor_common(struct drm_device *dev,
 	ret = drm_modeset_lock(&crtc->mutex, &ctx);
 	if (ret)
 		goto out;
-	ret = drm_modeset_lock(&crtc->cursor->mutex, &ctx);
-	if (ret)
-		goto out;
-
 	/*
 	 * If this crtc has a universal cursor plane, call that plane's update
 	 * handler rather than using legacy cursor handlers.
 	 */
 	if (crtc->cursor) {
+		ret = drm_modeset_lock(&crtc->cursor->mutex, &ctx);
+		if (ret)
+			goto out;
+
 		ret = drm_mode_cursor_universal(crtc, req, file_priv, &ctx);
 		goto out;
 	}
-- 
2.11.0