linux-kernel - [PATCH v2 1/2] drm/ssd130x: fix ssd132x encoding

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20250115110139.1672488-2-jkeeping@inmusicbrands.com>
Date: Wed, 15 Jan 2025 11:01:37 +0000
From: John Keeping <jkeeping@...usicbrands.com>
To: Javier Martinez Canillas <javierm@...hat.com>
Cc: John Keeping <jkeeping@...usicbrands.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] drm/ssd130x: fix ssd132x encoding

The ssd132x buffer is encoded one pixel per nibble, with two pixels in
each byte.  When encoding an 8-bit greyscale input, take the top 4-bits
as the value and ensure the two pixels are distinct and do not overwrite
each other.

Fixes: fdd591e00a9c ("drm/ssd130x: Add support for the SSD132x OLED controller family")
Signed-off-by: John Keeping <jkeeping@...usicbrands.com>
Reviewed-by: Javier Martinez Canillas <javierm@...hat.com>
---
Changes since v1:
- Correct a typo in the commit message
- Add Fixes and Reviewed-by tags (thanks Javier!)

 drivers/gpu/drm/solomon/ssd130x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
index b777690fd6607..4bb663f984ce3 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -880,7 +880,7 @@ static int ssd132x_update_rect(struct ssd130x_device *ssd130x,
 			u8 n1 = buf[i * width + j];
 			u8 n2 = buf[i * width + j + 1];
 
-			data_array[array_idx++] = (n2 << 4) | n1;
+			data_array[array_idx++] = (n2 & 0xf0) | (n1 >> 4);
 		}
 	}
 
-- 
2.48.0