[PATCH v2] drm/bridge-connector: Prioritize supported_formats over ycbcr_420_allowed

From: Cristian Ciocaltea
Date: Fri Dec 06 2024 - 15:01:12 EST


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 ignoring ycbcr_420_allowed for HDMI bridges
and, instead, make use of the supported_formats bitmask when setting up
the bridge connector.

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>
---
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@xxxxxxxxxxxxx
---
drivers/gpu/drm/display/drm_bridge_connector.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 320c297008aaa8b6ef5b1f4c71928849b202e8ac..1f05278b8683a25a845f943720c76faeed24c2e2 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -414,7 +414,7 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
drm_for_each_bridge_in_chain(encoder, bridge) {
if (!bridge->interlace_allowed)
connector->interlace_allowed = false;
- if (!bridge->ycbcr_420_allowed)
+ if (!bridge->ycbcr_420_allowed && !(bridge->ops & DRM_BRIDGE_OP_HDMI))
connector->ycbcr_420_allowed = false;

if (bridge->ops & DRM_BRIDGE_OP_EDID)
@@ -436,6 +436,10 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,

if (bridge->supported_formats)
supported_formats = bridge->supported_formats;
+
+ if (!(bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV420)))
+ connector->ycbcr_420_allowed = false;
+
if (bridge->max_bpc)
max_bpc = bridge->max_bpc;
}
@@ -459,7 +463,10 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
if (connector_type == DRM_MODE_CONNECTOR_Unknown)
return ERR_PTR(-EINVAL);

- if (bridge_connector->bridge_hdmi)
+ if (bridge_connector->bridge_hdmi) {
+ if (!connector->ycbcr_420_allowed)
+ supported_formats &= ~BIT(HDMI_COLORSPACE_YUV420);
+
ret = drmm_connector_hdmi_init(drm, connector,
bridge_connector->bridge_hdmi->vendor,
bridge_connector->bridge_hdmi->product,
@@ -468,10 +475,11 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
connector_type, ddc,
supported_formats,
max_bpc);
- else
+ } else {
ret = drmm_connector_init(drm, connector,
&drm_bridge_connector_funcs,
connector_type, ddc);
+ }
if (ret)
return ERR_PTR(ret);


---
base-commit: f486c8aa16b8172f63bddc70116a0c897a7f3f02
change-id: 20241130-bridge-conn-fmt-prio-c517c1407ed5