drm/plane-helper: Test for plane disable earlier

drm_plane_helper_check_update() currently uses crtc before testing whether
we're disabling the plane (fb == NULL).  Move the fb test before the first crtc
usage so that crtc == NULL doesn't have to be handled by the caller.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 11 insertions, 5 deletions

diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
index 18a1ac6ac22f..391dfb7d1086 100644
--- a/drivers/gpu/drm/drm_plane_helper.c
+++ b/drivers/gpu/drm/drm_plane_helper.c
@@ -142,6 +142,17 @@ int drm_plane_helper_check_update(struct drm_plane *plane,
 {
         int hscale, vscale;
 
+        if (!fb) {
+                *visible = false;
+                return 0;
+        }
+
+        /* crtc should only be NULL when disabling (i.e., !fb) */
+        if (WARN_ON(!crtc)) {
+                *visible = false;
+                return 0;
+        }
+
         if (!crtc->enabled && !can_update_disabled) {
                 DRM_DEBUG_KMS("Cannot update plane of a disabled CRTC.\n");
                 return -EINVAL;
@@ -155,11 +166,6 @@ int drm_plane_helper_check_update(struct drm_plane *plane,
                 return -ERANGE;
         }
 
-        if (!fb) {
-                *visible = false;
-                return 0;
-        }
-
         *visible = drm_rect_clip_scaled(src, dest, clip, hscale, vscale);
         if (!*visible)
                 /*