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SubjectRe: APM

> I did get apm to function, but it wasn't the way i wanted. I set an
> inactivity timeout in the bios and after that period of time, the cpu
> did indeed downshift. *However*, when the cpu became non-inactive,
> the bios did not speed the cpu up. Apparently, the bios was simply
> monitoring things like key presses to determine inactivity. I would
> like to set it up so that the kernel decides when it is inactive and
> when it is not. That way, when left unattended, the cpu could slow
> down and speed up according to cpu demand (since there is a great deal
> of unattended activity) and not simply user interaction at the
> console.

I think you only have power management, not APM. In an APM situation, the
kernel would tell the BIOS when to switch between power-saving states.
I do not know how much support for APM there is in the kernel (besides an
APM option in make config).

> This type of setup may not be possible. The ami bios documentation is
> very terse and I find even less documentation for the linux side.

Use your favorite search engine to look for the APM BIOS spec:
Advanced Power Management. (APM) BIOS Interface Specification. Revision 1.1.
September 1993.
Then take a look at the "CPU idle" and "CPU busy" calls.

Kimon Berlin - Hewlett-Packard Performance Desktop Computing Operation R&D
(BIOS), a spinoff of the Division Formerly Known as GPCD
"You can tune a filesystem, but you can't tune a fish" [HP/UX tunefs(1M)]

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