Hi!
> > > Actually, it just occurred to me that if we're waiting for a system
> > > timer and can hand that off to a suitable timer in the PMIC then we can
> > > do a suspend to RAM for the deep idle state from the hardware point of
> > > view.
> >
> > Yep. At LinuxCon Cambridge two years ago, we had a discussion about
> > whether it would be possible to enter ACPI S-states from CPUIdle (or some
> > idle governor) on Intel chips. If I remember correctly, the conclusion
> > was that ACPI always disables the screen/backlight, so it would only be
> > useful for situations where that was acceptable.
Well, auto suspending when screensaver is active would still be
useful.
(And IIRC some machines kept screen on when in S-state unless driver
powered it down... but that might be S1.
> The reason why you can't enter ACPI S-states from CPUidle is because you
> need to go out of the idle loop to execute some ACPI-specific stuff. Which
> is not even specific to Intel chips, but to ACPI in general.
The code was little tricky/unclean, but it "worked" for me at one
point... I called it "sleepy linux".
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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