Specifies the port for which PortNotify events are to be generated
when its attributes are changed using XvSetPortAttribute(3).
onoff
Specifies whether notification is to be enabled or disabled.
Description
XvSelectPortNotify(3) enables or disables PortNotify event
delivery to the requesting client. XvPortNotify(3) events are
generated when port attributes are changed using XvSetPortAttribute(3).