From: Ville Syrjälä ville.syrjala@linux.intel.com
The PATH blob is already being parsed by userspace for MST connectors so the layout of the blob is now uabi. Let's document what it should look like.
Also add a clear note saying non-MST connectors can have a PATH prop too.
Cc: Daniel Vetter daniel@ffwll.ch Cc: Pekka Paalanen ppaalanen@gmail.com Cc: Ilia Mirkin imirkin@alum.mit.edu Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com --- drivers/gpu/drm/drm_connector.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index e17586aaa80f..ce3926e9ad11 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -899,7 +899,16 @@ static const struct drm_prop_enum_list hdmi_colorspaces[] = { * connected. Used by DP MST. This should be set by calling * drm_connector_set_path_property(), in the case of DP MST with the * path property the MST manager created. Userspace cannot change this - * property. + * property. The value must be an ASCII string. + * + * For DP MST connectors the path string follows the pattern + * "mst:<base connector ID>[-<mst port>]...", where the base connector ID + * identifies the DP connector on the source device, and the mst ports + * are the port numbers in the DP MST topology. + * + * For non-DP MST connectors the format is freeform, as long as it + * uniquely identifies the physical path, remains stable across + * kernel releases, and does not start with "mst:". * TILE: * Connector tile group property to indicate how a set of DRM connector * compose together into one logical screen. This is used by both high-res @@ -1678,7 +1687,7 @@ int drm_mode_create_suggested_offset_properties(struct drm_device *dev) EXPORT_SYMBOL(drm_mode_create_suggested_offset_properties);
/** - * drm_connector_set_path_property - set tile property on connector + * drm_connector_set_path_property - set path property on connector * @connector: connector to set property on. * @path: path to use for property; must not be NULL. *