drm/exynos: decon5433: Fix per-plane global alpha for XRGB modes

BugLink: https://bugs.launchpad.net/bugs/1792377

[ Upstream commit ab337fc2 ]

Set per-plane global alpha to maximum value to get proper blending of
XRGB and ARGB planes. This fixes the strange order of overlapping planes.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/gpu/drm/exynos/exynos5433_drm_decon.c

@@ -278,8 +278,8 @@ static void decon_update_plane(struct exynos_drm_crtc *crtc,
 		COORDINATE_Y(plane->crtc_y + plane->crtc_h - 1);
 	writel(val, ctx->addr + DECON_VIDOSDxB(win));
 
-	val = VIDOSD_Wx_ALPHA_R_F(0x0) | VIDOSD_Wx_ALPHA_G_F(0x0) |
-		VIDOSD_Wx_ALPHA_B_F(0x0);
+	val = VIDOSD_Wx_ALPHA_R_F(0xff) | VIDOSD_Wx_ALPHA_G_F(0xff) |
+		VIDOSD_Wx_ALPHA_B_F(0xff);
 	writel(val, ctx->addr + DECON_VIDOSDxC(win));
 
 	val = VIDOSD_Wx_ALPHA_R_F(0x0) | VIDOSD_Wx_ALPHA_G_F(0x0) |