Another thing that is missing in the G_TOPOLOGY ioctl are the entity flags
MEDIA_ENT_FL_DEFAULT and MEDIA_ENT_FL_CONNECTOR.
The DEFAULT flag should be part of the interface flags (it describes which
interface is the default). The CONNECTOR flag should be a new field in the
media_v2_entity struct. In theory it is possible to deduce this from the
entity ID, but I think that's a bad idea.
I'm not sure if the DEFAULT flag would also make sense for an entity as
opposed to an interface. I don't think so.