From: Damon Ding Date: Wed, 17 Dec 2025 09:33:04 +0000 (+0800) Subject: drm/display: bridge_connector: Ensure last bridge determines EDID/modes detection... X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3c05e956b85e70cbd5042e03f615b23ca4635385;p=thirdparty%2Fkernel%2Flinux.git drm/display: bridge_connector: Ensure last bridge determines EDID/modes detection capabilities When multiple bridges are present, EDID detection capability (DRM_BRIDGE_OP_EDID) takes precedence over modes detection (DRM_BRIDGE_OP_MODES). To ensure the above two capabilities are determined by the last bridge in the chain, we handle three cases: Case 1: The later bridge declares only DRM_BRIDGE_OP_MODES - If the previous bridge declares DRM_BRIDGE_OP_EDID, set &drm_bridge_connector.bridge_edid to NULL and set &drm_bridge_connector.bridge_modes to the later bridge. - Ensure modes detection capability of the later bridge will not be ignored. Case 2: The later bridge declares only DRM_BRIDGE_OP_EDID - If the previous bridge declares DRM_BRIDGE_OP_MODES, set &drm_bridge_connector.bridge_modes to NULL and set &drm_bridge_connector.bridge_edid to the later bridge. - Although EDID detection capability has higher priority, this operation is for balance and makes sense. Case 3: the later bridge declares both of them - Assign later bridge as &drm_bridge_connector.bridge_edid and and &drm_bridge_connector.bridge_modes to this bridge. - Just leave transfer of these two capabilities as before. Signed-off-by: Damon Ding Suggested-by: Dmitry Baryshkov Tested-by: Marek Szyprowski Reviewed-by: Luca Ceresoli Tested-by: Heiko Stuebner (on rk3588) Link: https://patch.msgid.link/20251217093321.3108939-2-damon.ding@rock-chips.com Signed-off-by: Luca Ceresoli --- diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c index ba8ff113cff12..d49ccf28d2b2b 100644 --- a/drivers/gpu/drm/display/drm_bridge_connector.c +++ b/drivers/gpu/drm/display/drm_bridge_connector.c @@ -826,9 +826,19 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm, if (!bridge->ycbcr_420_allowed) connector->ycbcr_420_allowed = false; - if (bridge->ops & DRM_BRIDGE_OP_EDID) { + /* + * Ensure the last bridge declares OP_EDID or OP_MODES or both. + */ + if (bridge->ops & DRM_BRIDGE_OP_EDID || bridge->ops & DRM_BRIDGE_OP_MODES) { drm_bridge_put(bridge_connector->bridge_edid); - bridge_connector->bridge_edid = drm_bridge_get(bridge); + bridge_connector->bridge_edid = NULL; + drm_bridge_put(bridge_connector->bridge_modes); + bridge_connector->bridge_modes = NULL; + + if (bridge->ops & DRM_BRIDGE_OP_EDID) + bridge_connector->bridge_edid = drm_bridge_get(bridge); + if (bridge->ops & DRM_BRIDGE_OP_MODES) + bridge_connector->bridge_modes = drm_bridge_get(bridge); } if (bridge->ops & DRM_BRIDGE_OP_HPD) { drm_bridge_put(bridge_connector->bridge_hpd); @@ -838,10 +848,6 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm, drm_bridge_put(bridge_connector->bridge_detect); bridge_connector->bridge_detect = drm_bridge_get(bridge); } - if (bridge->ops & DRM_BRIDGE_OP_MODES) { - drm_bridge_put(bridge_connector->bridge_modes); - bridge_connector->bridge_modes = drm_bridge_get(bridge); - } if (bridge->ops & DRM_BRIDGE_OP_HDMI) { if (bridge_connector->bridge_hdmi) return ERR_PTR(-EBUSY);