Re: understanding acpi

Rodney Cacy
2006-12-04T12:21:24Z

I'm not an expert but you can pass a boot kernel option:

processor.max_cstate

More inforamtion in http://www.columbia.edu/~ariel/acpi/acpi_howto.txt,
section 7.
Write me about the results. Now I'm working under suspending sound,lan
etc. to save battery but soon I will work with the noise reduction.

Cacy

Oliver Henriot wrote:
> Hi all list subscribers,
>
> I'm looking for info on how acpi functions in order to get it to work
> the best possible on my computer. It's a Sony laptop (vaio vgn-sz3xp/c,
> core2duo) running Debian Etch. In particular, I'm looking for ways to
> reduce thermal dissipation from the CPU as much as possible, in order to
> queep the machine as quiet as possible. From the various docs I've read,
> so far I seem to understand that C-states is the way to go, throttling
> being probably not very efficient.
>
> When I'm running on batteries, C3 state is active (as shown by cat
> /prc/acpi/processor/CPU0/power) and is the main state, whereas when I'm
> running on mains, C3 disappears and only C1 and C2 remain.
>
> My question are : wouldn't it be better if I could use C3 even when on
> mains. Wouldn't it be even better with C4? As suggested by "Why My Cx
> Power State Is Not Used" I tried unloading various modules (e.g. those
> concerning usb but I got stuck with usbcore which refused to unload
> despite nothing usb being connected) without any success. Being
> relatively new to GNU/Linux, I'm a bit stuck here and don't know where
> to look or what to make of this.
>
> Any help would be gladly welcome.
>
> Cheers,
>
> Oliver
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