[PATCH v3 0/2] Fix ycbcr_420_allowed inconsistency for HDMI bridges

[Cristian Ciocaltea]

Bridges with DRM_BRIDGE_OP_HDMI set in drm_bridge->ops are expected to
rely on drm_bridge->supported_formats to advertise the supported
colorspaces, including HDMI_COLORSPACE_YUV420.

However, when drm_bridge_connector gets initialised, only
drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
the drm_connector->ycbcr_420_allowed, which effectively discards the
formats advertised by the HDMI bridge.

This patchset tries to address the issue by prioritizing
supported_formats over ycbcr_420_allowed.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea at collabora.com>
---
Changes in v3:
- Simplified the inconsistency handling by overwriting ycbcr_420_allowed
  for HDMI bridges before adding them to the global bridge list
- Added a 2nd patch to check if supported_formats matches
  ycbcr_420_allowed on HDMI connector initialization (Dmitry)
- Link to v2: https://lore.kernel.org/r/20241206-bridge-conn-fmt-prio-v2-1-85c817529b88@collabora.com

Changes in v2:
- Wrapped HDMI_COLORSPACE_YUV420 flag in the BIT() macro to properly
  check its presence in supported_formats
- Ensured YUV420 gets removed from the bitmask passed to
  drmm_connector_hdmi_init() when ycbcr_420_allowed is not set
- Link to v1: https://lore.kernel.org/r/20241130-bridge-conn-fmt-prio-v1-1-146b663f17f3@collabora.com

---
Cristian Ciocaltea (2):
      drm/bridge-connector: Prioritize supported_formats over ycbcr_420_allowed
      drm/connector: hdmi: Validate supported_formats matches ycbcr_420_allowed

 drivers/gpu/drm/display/drm_bridge_connector.c | 8 ++++++--
 drivers/gpu/drm/drm_bridge.c                   | 4 ++++
 drivers/gpu/drm/drm_connector.c                | 3 +++
 3 files changed, 13 insertions(+), 2 deletions(-)
---
base-commit: f486c8aa16b8172f63bddc70116a0c897a7f3f02
change-id: 20241130-bridge-conn-fmt-prio-c517c1407ed5