*     As userspace can't currently know whether or not the output is using
 *     RGB or YCC signalling, the driver must translate properties to their
 *     relevant RGB or YCC counterparts, depending on the actually used
 *     signalling. Property values that are only valid for either YCC or RGB
 *     and have no equivalent for the other signalling type must not be
 *     exposed as supported, unless the driver can guarantee it never uses
 *     the signalling that doesn't match the property.