HDMI uses the DDC I2C bus for communicating various bits of link status
out of band with the actual HDMI video signal. This information can be
useful for debugging issues like questionable cables sabotaged by feline
teeth, Enthusiast Grade cables made of cow fencing wire, and other such
problems that ruin one's media viewing plans.
Consequently, this series exposes various bits of pertinent information
from the SCDC protocol in an HDMI connector's debugfs. To continually
poll the link status, userspace can poll the debugfs file.
---
Changes in v2:
- Add HDMI 2.1 SCDC status reporting
- Link to v1: https://patch.msgid.link/20260415-scdc-link-health-v1-0-8e731e88eaf0@collabora.com
To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
To: Maxime Ripard <mripard@kernel.org>
To: Thomas Zimmermann <tzimmermann@suse.de>
To: David Airlie <airlied@gmail.com>
To: Simona Vetter <simona@ffwll.ch>
To: Andrzej Hajda <andrzej.hajda@intel.com>
To: Neil Armstrong <neil.armstrong@linaro.org>
To: Robert Foss <rfoss@kernel.org>
To: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
To: Jonas Karlman <jonas@kwiboo.se>
To: Jernej Skrabec <jernej.skrabec@gmail.com>
To: Luca Ceresoli <luca.ceresoli@bootlin.com>
To: Daniel Stone <daniel@fooishbar.org>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Cc: kernel@collabora.com
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
Nicolas Frattaroli (3):
drm/scdc-helper: Add scdc_status debugfs entry
drm/display: bridge_connector: init scdc debugfs for HDMI
drm/scdc-helper: Implement parsing and printing HDMI 2.1 fields
drivers/gpu/drm/display/drm_bridge_connector.c | 4 +
drivers/gpu/drm/display/drm_scdc_helper.c | 341 +++++++++++++++++++++++++
include/drm/display/drm_scdc.h | 9 +
include/drm/display/drm_scdc_helper.h | 113 ++++++++
4 files changed, 467 insertions(+)
---
base-commit: 7d39df83e93eba14a23b1fb6ffff076eb191f27b
change-id: 20260413-scdc-link-health-89326013d96c
Best regards,
--
Nicolas Frattaroli <nicolas.frattaroli@collabora.com>