Re: Hibernation considerations

Rafael J. Wysocki
2007-07-17T21:32:53Z

On Tuesday, 17 July 2007 23:06, david@lang.hm wrote:
> On Tue, 17 Jul 2007, Jeremy Maitin-Shepard wrote:
>
> > david@lang.hm writes:
> >
> > [snip]
> >
> >>>> * figure out which devices can wake up
> >>>> * put devices into low power states (wake-up devices are placed in the Dx
> >>>> states compatible with the wake capability, the others are powered off)
> >
> >> this can't be done by the image-saving kernel if that kernel doesn't know about
> >> the device.
> >
> > The image-saving kernel can be made to know about all of the "wake up"
> > devices; all other devices should have already been powered off by the
> > "hibernated" kernel.
>
> not nessasarily.

More than that. The hibernated kernel should not power off any devices,
because that is _wasteful_ (unless, of course, the powering off a device is the
only way to quiesce it).

Greetings,
Rafael

--
"Premature optimization is the root of all evil." - Donald Knuth