On Tue, Dec 17, 2024 at 12:54:07AM +0200, Cristian Ciocaltea wrote:
> Bridges having the DRM_BRIDGE_OP_HDMI flag set in drm_bridge->ops are
> supposed to rely on drm_bridge->supported_formats bitmask to advertise
> the supported colorspaces, including HDMI_COLORSPACE_YUV420. Therefore,
> the newly introduced drm_bridge->ycbcr_420_allowed flag becomes
> redundant in this particular context.
>
> Moreover, when drm_bridge_connector gets initialised, only
> drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
> the equivalent property of the base drm_connector, which effectively
> discards the formats advertised by the HDMI bridge.
>
> Handle the inconsistency by overwriting drm_bridge->ycbcr_420_allowed
> for HDMI bridges according to drm_bridge->supported_formats, before
> adding them to the global bridge list.
>
> Additionally, ensure the YUV420 related bit is removed from the bitmask
> passed to drmm_connector_hdmi_init() when the final ycbcr_420_allowed
> flag for the connector ends up not being set (i.e. the case of having at
> least one non-HDMI bridge in the pipeline that didn't enable it).
>
> Fixes: 3ced1c687512 ("drm/display: bridge_connector: handle ycbcr_420_allowed")
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/display/drm_bridge_connector.c | 8 ++++++--
> drivers/gpu/drm/drm_bridge.c | 4 ++++
> 2 files changed, 10 insertions(+), 2 deletions(-)
I think the second patch in the series is enough, it ensures that
connector's state is consistent, no matter if the drm_bridge_connector
is being used or a normal drm_connector.
Nevertheless, I'd leave the final decision to DRM maintainers.
--
With best wishes
Dmitry
