Re: A minimally power-aware driver treats all messages as SUSPEND?

[Rafael J. Wysocki]

On Tuesday, 1 of July 2008, Uwe Kleine-König wrote:
> Hello Rafael,
> 
> Rafael J. Wysocki wrote:
> > On Tuesday, 1 of July 2008, Uwe Kleine-König wrote:
> > > include/linux/pm.h claims:
> > >
> > >       A minimally power-aware driver treats all messages as SUSPEND
> > >       [...].
> > >
> > > This was introduced in commit 82bb67f2 by David Brownell.  At this time
> > > PM_EVENT_HIBERNATE didn't exist.  This was added in 3a2d5b70 by Rafael
> > > J. Wysocki without updating the above sentence.  I think a minimally
> > > power-aware driver should treat all messages as HIBERNATE, shouldn't it?
> > 
> > No, I don't think so.  In the majority of cases, SUSPEND is equivalent to the
> > combination of FREEZE and HIBERNATE.
> I didn't get that.  I thought SUSPEND is suspend-to-ram and HIBERNATE is
> suspend-to-disk, so HIBERNATE is the "deeper sleep".
> With that I might have to do less on SUSPEND because some state might be
> preserved after the machine comes up again.
> 
> > Still, this is going to change anyway with the introduction of the new
> > suspend/hibernation callbacks that are scheduled for 2.6.27.
> in next?

Yes.

Thanks,
Rafael
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