[PATCH v4 04/41] drm: renesas: shmobile: Fix overlay plane disable

[Geert Uytterhoeven]

Merely writing zero to the CHn Source Image Format Register is not
sufficient to disable a plane, as the programmed register value is not
propagated immediately to the current side.  This can be seen when using
the -P option of modetest: the extra plane is displayed correctly, but
does not disappear after exit.

Fix this by doing the full update dance using the Blend Control
Register, like is done when enabling the plane.

Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
---
v4:
  - No changes,

v3:
  - No changes,

v2:
  - Add Reviewed-by.
---
 drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c
index 850986cee848226a..0e34573c3cb3d032 100644
--- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c
+++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c
@@ -215,7 +215,10 @@ static int shmob_drm_plane_disable(struct drm_plane *plane,
 
 	splane->format = NULL;
 
+	lcdc_write(sdev, LDBCR, LDBCR_UPC(splane->index));
 	lcdc_write(sdev, LDBnBSIFR(splane->index), 0);
+	lcdc_write(sdev, LDBCR,
+		   LDBCR_UPF(splane->index) | LDBCR_UPD(splane->index));
 	return 0;
 }
 
-- 
2.34.1