Re: USB runtime D3

Matthew Garrett
2009-07-30T19:26:03Z

On Thu, Jul 30, 2009 at 03:22:32PM -0400, Alan Stern wrote:

> Seems likely. What happens if you suspend the UHCI controller but
> leave the EHCI controller active? Then the port-switching logic should
> kick in.

Yeah, I'll give that a go.

> Which reminds me... One of the things you had to do was enable remote
> wakeup for the host controllers. The current initial state is
> disabled, for a good reason. People don't like it if they suspend
> their laptop only to find that the computer wakes back up again when
> they unplug the USB mouse.
>
> If we do end up implementing runtime power management for USB host
> controllers, something (a userspace program?) will have to turn off
> remote wakeup before system sleeps and turn it back on afterward.

I think we'll probably want a call for "transitioning from runtime
suspend to system suspend", at which point the driver can clean that up
itself.

--
Matthew Garrett | mjg59@srcf.ucam.org