[PATCH 1/7] drm/plane-helper: Test for plane disable earlier

[Matt Roper]

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 at intel.com>
---
 drivers/gpu/drm/drm_plane_helper.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
index ae61fb2..f24c4cf 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)
 		/*
-- 
1.8.5.1