For DP bridges, that can be used for DP AltMode, it might be necessary to enforce HPD status. There is an existing ->oob_hotplug_event() on the DRM connector, but it currently just calls into hpd_notify().
As DP bridge drivers usually also implement .detect and that also generates calls into hpd_notify, this is a bad place to force the HPD status as the follow-up detect call might force it off again resulting in all follow-up calls to the detection routine also failing. Avoid this by having a dedicated function for OOB events. Signed-off-by: Sebastian Reichel <[email protected]> --- drivers/gpu/drm/display/drm_bridge_connector.c | 6 ++++++ include/drm/drm_bridge.h | 14 ++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c index 92f8a2d7aab4..802b5677194b 100644 --- a/drivers/gpu/drm/display/drm_bridge_connector.c +++ b/drivers/gpu/drm/display/drm_bridge_connector.c @@ -180,6 +180,12 @@ static void drm_bridge_connector_oob_hotplug_event(struct drm_connector *connect struct drm_bridge_connector *bridge_connector = to_drm_bridge_connector(connector); + /* Notify all bridges in the pipeline of hotplug events. */ + drm_for_each_bridge_in_chain_scoped(bridge_connector->encoder, bridge) { + if (bridge->funcs->oob_notify) + bridge->funcs->oob_notify(bridge, connector, status); + } + drm_bridge_connector_handle_hpd(bridge_connector, status); } diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 00a95f927e34..11802e39d1f1 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -646,6 +646,20 @@ struct drm_bridge_funcs { */ void (*hpd_disable)(struct drm_bridge *bridge); + /** + * @oob_notify: + * + * Notify the bridge of out of band hot plug detection. + * + * This callback is optional, it may be implemented by bridges that + * need to be notified of display connection or disconnection for + * internal reasons. One use case is to force the DP controllers HPD + * signal for USB-C DP AltMode. + */ + void (*oob_notify)(struct drm_bridge *bridge, + struct drm_connector *connector, + enum drm_connector_status status); + /** * @hdmi_tmds_char_rate_valid: * -- 2.53.0
