Extracted from SiS's GPLed driver. From the few pdf available at SiS's,
it seems that the 965 and the 966 south bridge include this interface
whereas the 965L (and anything below) does not. It is expected to be a
sis191 related feature and should not hurt the existing sis190 driver.
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>