linux-kernel - [PATCH v2 0/2] drm/vkms: Fix bad matrix offset component multiplication

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-next>] [day] [month] [year] [list]

Message-Id: <20260210-vkms-composer-fix-matrix-v2-0-d1ed09cb23e8@collabora.com>
Date: Tue, 10 Feb 2026 14:43:59 -0300
From: Ariel D'Alessandro <ariel.dalessandro@...labora.com>
To: Louis Chauvet <louis.chauvet@...tlin.com>, 
 Haneen Mohammed <hamohammed.sa@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Melissa Wen <melissa.srw@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 nfraprado@...labora.com, pekka.paalanen@...labora.com, 
 daniels@...labora.com, kernel@...labora.com, 
 Ariel D'Alessandro <ariel.dalessandro@...labora.com>
Subject: [PATCH v2 0/2] drm/vkms: Fix bad matrix offset component
 multiplication

This patch series fixes a bug in the 3x4 matrix multiplication for BT709
enconding/decoding, where the offset component if not handled properly.

Currently, BT.709 encoding matrix kunit tests don't cover the offset
component multiplication, so a new set of tests is added.

The bug was found while working on the IGT tools CRTC (post-blend) color
pipelines, see submitted patchset [0] (patch [1] in particular) for the
full context.

[0] https://lore.kernel.org/igt-dev/20251223-post-blend-colorops-v2-0-f40aca9795bd@collabora.com/
[1] https://lore.kernel.org/igt-dev/20251223-post-blend-colorops-v2-7-f40aca9795bd@collabora.com/

Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@...labora.com>
---
Changes in v2:
- Added kunit tests for alternative BT709 encoding matrix.
- Link to v1: https://lore.kernel.org/r/20251223-vkms-composer-fix-matrix-v1-1-10a979e06209@collabora.com

---
Ariel D'Alessandro (2):
      drm/vkms: Fix bad matrix offset component multiplication
      drm/vkms: Add kunit tests for alternative BT709 encoding matrix

 drivers/gpu/drm/vkms/tests/vkms_color_test.c | 146 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_composer.c         |  13 ++-
 2 files changed, 156 insertions(+), 3 deletions(-)
---
base-commit: b96bcfba104c65db41378a04f5ccac186f79578f
change-id: 20251223-vkms-composer-fix-matrix-aa2c593f4515

Best regards,
-- 
Ariel D'Alessandro <ariel.dalessandro@...labora.com>