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 <[email protected]> Suggested-by: Dmitry Baryshkov <[email protected]> Tested-by: Marek Szyprowski <[email protected]> --- Changes in v7: - As Luca suggested, simplify the code and related comment. Changes in v8: - Adapt the modifications to the newest bridge_connector driver. --- drivers/gpu/drm/display/drm_bridge_connector.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c index a2d30cf9e06d..92b9e8ec520d 100644 --- a/drivers/gpu/drm/display/drm_bridge_connector.c +++ b/drivers/gpu/drm/display/drm_bridge_connector.c @@ -690,9 +690,19 @@ 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); @@ -702,10 +712,6 @@ 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); -- 2.34.1
