Re: [PATCH] usb: Add support for runtime power management of the hcd

Matthew Garrett
2009-11-12T14:50:26Z

On Thu, Nov 12, 2009 at 11:31:05AM +0100, Oliver Neukum wrote:
> Am Mittwoch, 11. November 2009 23:24:57 schrieb Rafael J. Wysocki:
> > > Now, this does raise another point, which has been mentioned before.
> > > To wit: devices really ought to have two remote-wakeup attributes,
> > > one for runtime PM and one for system sleep.
> >
> > Yes, they do and there's another reason. Namely, there apparently are
> > devices which can wake up the system from a sleep state and that are
> > unable to generate runtime wakeup events.
>
> That is outright disgusting. Which devices do this?

The ability for a device to raise an ACPI GPE and trigger a wakeup does
not imply that there's runtime handling for that device's GPE in the
system's ACPI tables. The default GPE handling code I posted for Intel
helps here, but there's ample opportunity for us to find machines which
have system wakeup support but no runtime wakeup support.

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