Re: Hibernate after alarm wakes from STR

David Brownell
2007-07-08T20:15:40Z

On Sunday 08 July 2007, Richard Hughes wrote:
> On Sun, 2007-07-08 at 12:17 -0700, David Brownell wrote:
> >
> > I think so ... although that's unfortunately another difference
> > between the legacy x86-mostly code and the newer RTC framework.
>
> (sorry for hijacking the thread)

I changed $SUBJECT ...

> Is this the interface should stuff like HAL use to do:
>
> * Suspend for 10 minutes
> * auto wakeup and then hibernate...

That is, "Suspend-to-RAM" or "standby"? Yes, assuming that works on
this particular system. Arguably that would be a direction for
cpuidle to think about too, but I think alarm-driven wakeup is more
ready-to-use at this point.

> I figure we can do a suspend setting the rtc using the ioctls and then
> we wakeup, and HAL has to know that we woke up from the alarm rather
> than from a lid event or keypress.

... although I don't know whether that particular distinction is
made to userspace right now. ACPI provides a bit like that, and
at least a few other systems can do something analagous.

That is, we may want to provide a bit more information about the
specific event which triggered wakeup. I don't believe there is
such an interface, in general.

Plus, the notion seems kind of racey to me. (If you press a key
right while the wakealarm fires, you don't want hibernation..)

> Is this something we can do (or should do) for OLPC and general ACPI?

I'd certainly rather see laptops doing that than what they do now:
running the battery out, and needing filesystem recovery!!

- Dave