[PATCH RFC 11/12] drm/bridge: Wire drmm_connector_dp_init() via new DRM_BRIDGE_OP_DP flag

Kory Maincent
2026-04-09T17:09:38Z

Introduce DRM_BRIDGE_OP_DP, a new bridge operation flag for bridges
that provide DisplayPort connector operations with link training support.
Bridges advertising this flag must fill the dp_link_train_caps field in
struct drm_bridge with their link training capabilities.

In drm_bridge_connector_init(), when a bridge sets DRM_BRIDGE_OP_DP,
use drmm_connector_dp_init() instead of the generic drmm_connector_init()
so the connector exposes link training state properties to userspace.
This mirrors the existing pattern used for HDMI bridges.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
---
drivers/gpu/drm/display/drm_bridge_connector.c | 26 +++++++++++++++++++++++++-
include/drm/drm_bridge.h | 13 +++++++++++++
2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 39cc18f78eda1..e20b61bb03f12 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -13,7 +13,7 @@
#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_bridge_connector.h>
-#include <drm/drm_connector.h>
+#include <drm/drm_dp_connector.h>
#include <drm/drm_device.h>
#include <drm/drm_edid.h>
#include <drm/drm_managed.h>
@@ -108,6 +108,13 @@ struct drm_bridge_connector {
* HDMI Audio infrastructure, if any (see &DRM_BRIDGE_OP_HDMI_AUDIO).
*/
struct drm_bridge *bridge_hdmi_audio;
+ /**
+ * @bridge_dp:
+ *
+ * The bridge in the chain that implements necessary support for the
+ * DisplayPort connector infrastructure, if any (see &DRM_BRIDGE_OP_DP).
+ */
+ struct drm_bridge *bridge_dp;
/**
* @bridge_dp_audio:
*
@@ -766,6 +773,7 @@ static void drm_bridge_connector_put_bridges(struct drm_device *dev, void *data)
drm_bridge_put(bridge_connector->bridge_hdmi_audio);
drm_bridge_put(bridge_connector->bridge_dp_audio);
drm_bridge_put(bridge_connector->bridge_hdmi_cec);
+ drm_bridge_put(bridge_connector->bridge_dp);
}

/**
@@ -898,6 +906,15 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
bridge_connector->bridge_hdmi_audio = drm_bridge_get(bridge);
}

+ if (bridge->ops & DRM_BRIDGE_OP_DP) {
+ if (bridge_connector->bridge_dp)
+ return ERR_PTR(-EBUSY);
+ if (!bridge->dp_link_train_caps)
+ return ERR_PTR(-EINVAL);
+
+ bridge_connector->bridge_dp = drm_bridge_get(bridge);
+ }
+
if (bridge->ops & DRM_BRIDGE_OP_DP_AUDIO) {
if (bridge_connector->bridge_dp_audio)
return ERR_PTR(-EBUSY);
@@ -986,6 +1003,13 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
max_bpc);
if (ret)
return ERR_PTR(ret);
+ } else if (bridge_connector->bridge_dp) {
+ ret = drmm_connector_dp_init(drm, connector,
+ &drm_bridge_connector_funcs,
+ bridge_connector->bridge_dp->dp_link_train_caps,
+ connector_type, ddc);
+ if (ret)
+ return ERR_PTR(ret);
} else {
ret = drmm_connector_init(drm, connector,
&drm_bridge_connector_funcs,
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index a8d67bd9ee505..b3df9dffd5bcc 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1092,6 +1092,14 @@ enum drm_bridge_ops {
* &drm_bridge_funcs->hdmi_clear_spd_infoframe callbacks.
*/
DRM_BRIDGE_OP_HDMI_SPD_INFOFRAME = BIT(10),
+ /**
+ * @DRM_BRIDGE_OP_DP: The bridge provides DisplayPort connector
+ * operations, including link training support. Bridges that set
+ * this flag must provide DisplayPort-related information and
+ * fill the &drm_bridge->dp_link_train_caps link training
+ * capabilities.
+ */
+ DRM_BRIDGE_OP_DP = BIT(11),
};

/**
@@ -1267,6 +1275,11 @@ struct drm_bridge {
*/
void *hpd_data;

+ /**
+ * @dp_link_train_caps: DisplayPort link training capabilities
+ */
+ const struct drm_connector_dp_link_train_caps *dp_link_train_caps;
+
/**
* @next_bridge: Pointer to the following bridge, automatically put
* when this bridge is freed (i.e. at destroy time). This is for

--
2.43.0