openwrt/target/linux/bcm27xx/patches-6.6/950-0902-vc4-hvs-Fix-lbm-size-calculation-for-yuv.patch

From 149228561318ce4b95f09329fca976856694b450 Mon Sep 17 00:00:00 2001
From: Dom Cobley <popcornmix@gmail.com>
Date: Fri, 16 Feb 2024 15:57:41 +0000
Subject: [PATCH 0902/1085] vc4/hvs: Fix lbm size calculation for yuv

The code was reducing the number of components by one when we were not
blending with alpha. But that only makes sense if the components include
alpha.

For YUV, we were reducing the number of components for Y from one to zero
which resulted in no lbm space being allocated.

Fixes: https://github.com/raspberrypi/linux/issues/5912
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
---
 drivers/gpu/drm/vc4/vc4_plane.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -742,7 +742,7 @@ static unsigned int vc4_lbm_channel_size
 	if (!components)
 		return 0;
 
-	if (state->alpha != DRM_BLEND_ALPHA_OPAQUE)
+	if (state->alpha != DRM_BLEND_ALPHA_OPAQUE && info->has_alpha)
 		components -= 1;
 
 	words = width * wpc * components;