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Re: ACPI on IBM Thinkpad T30



On Wed, 19 Nov 2003 00:18:22 -0500
Mike Phillips <phillim2@comcast.net> wrote:

> Non ACPI just gives you two speeds to work with, full 1.8 and slow
> 1.2. 
> 
> echo "1200000:1800000:powersave" > /proc/cpufreq.
> echo "1200000:1800000:performance" > /proc/cpufreq to restore.

awesome. It seems I can even get it down to 250 MHz. The system would
get really slow and /proc/cpuinfo would show the right frequency. But
when measured with specific tools (eg x86info), they all find the
CPU running at 2GHz (I have a 2GHz T30). These tools do not just read
the identifier, they actually _measure_ the frequency.

> You can actually tweak the cpu through the acpi interface too: 
> 
> echo "N" > /proc/acpi/processor/CPU/throttling where 0 <= N <= 7. 
> 
> This really does work, try it with "7" and watch the system crawl, not
> sure if this saves any power though. 

This seems to just throttle the CPU by putting load on it. After
`echo 7 > /proc/acpi/processor/CPU/throttling` the system becomes
really slow because of CPU load. It is certainly not the best way to
save power :)

But are there some daemons around, which switch the frequency depending
on CPU load? That's what I need in the first place. Compiling should be
really fast (2GHz) but I don't mind having the CPU at 250MHz while
working. The switch should automatically be done in background.

> > 1) Seen in dmesg:
> >       i810_audio: Audio Controller supports 6 channels.
> >       i810_audio: Defaulting to base 2 channel mode.
> >    Can I enable 6 channels? currently I have to stop XMMS (so that
> >    /dev/dsp gets released) to get sound in another application. Is
> >    there a workaround to this issue or is it hardware specific (I
> >    don't think it is, because Windows handles more than one input)?
> 
> Not sure on this one, I'm using Alsa so it lets me have multiple apps
> running sound and there's no spdif out on my machine to get at the 6
> channels anyway. 

I might give ALSA a try...

Cheersm
Serge



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