David Airlie and Matthew Garrett have done some more investigations and the current roadmap for switchable graphics in Linux looks like this:
_OFF methods are abstracted behind the ones above, so they shouldn't be used directly.
Hot switching:
Given a on/off switch event, the switch will be delayed until the X.Org Server is restarted. This will need a switch call, then a log-out and GDM restart.
- ATI/ATI and Intel/ATI configurations will use ATPX and maybe XPTX calls.
- Intel/nvidia and nvidia/nvidia configurations will use _DCM related calls.
_OFF methods are abstracted behind the ones above, so they shouldn't be used directly.
Hot switching:
Given a on/off switch event, the switch will be delayed until the X.Org Server is restarted. This will need a switch call, then a log-out and GDM restart.