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>

diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
index 18a1ac6..391dfb7 100644 (file)
--- 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)
                /*