linux-kernel - [PATCH RFC 1/6] drm/mediatek: plane: Remove extra block from AFBC data payload offset

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251230-mtk-afbc-fixes-v1-1-6c0247b66e32@collabora.com>
Date: Tue, 30 Dec 2025 11:03:01 -0300
From: Nícolas F. R. A. Prado <nfraprado@...labora.com>
To: Chun-Kuang Hu <chunkuang.hu@...nel.org>, 
 Philipp Zabel <p.zabel@...gutronix.de>, David Airlie <airlied@...il.com>, 
 Simona Vetter <simona@...ll.ch>, Matthias Brugger <matthias.bgg@...il.com>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Justin Green <greenjustin@...omium.org>
Cc: kernel@...labora.com, dri-devel@...ts.freedesktop.org, 
 linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, ariel.dalessandro@...labora.com, 
 daniels@...labora.com, kernel@...labora.com, Nancy.Lin@...iatek.com, 
 Jason-JH.Lin@...iatek.com, 
 Nícolas F. R. A. Prado <nfraprado@...labora.com>
Subject: [PATCH RFC 1/6] drm/mediatek: plane: Remove extra block from AFBC
 data payload offset

The AFBC data payload is in fact not offset by 1 additional block as the
code and comment suggest, and this causes the buffer to be rendered
offset by one block. Remove this extraneous offset to get the buffer
correctly displayed.

Fixes: c410fa9b07c3 ("drm/mediatek: Add AFBC support to Mediatek DRM driver")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>
---
 drivers/gpu/drm/mediatek/mtk_plane.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_plane.c b/drivers/gpu/drm/mediatek/mtk_plane.c
index 5043e0377270..1214f623859e 100644
--- a/drivers/gpu/drm/mediatek/mtk_plane.c
+++ b/drivers/gpu/drm/mediatek/mtk_plane.c
@@ -164,10 +164,9 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state,
 		 */
 		hdr_addr = addr + hdr_offset;

-		/* The data plane is offset by 1 additional block. */
 		offset = pitch * y_offset_in_blocks +
 			 AFBC_DATA_BLOCK_WIDTH * AFBC_DATA_BLOCK_HEIGHT *
-			 fb->format->cpp[0] * (x_offset_in_blocks + 1);
+			 fb->format->cpp[0] * x_offset_in_blocks;

 		/*
 		 * Using dma_addr_t variable to calculate with multiplier of different types,

-- 
2.51.0