[ltp] acpi cpu controll

[Tino Keitel]

On Thu, May 01, 2003 at 15:30:26 +0200, Gregor R. Goldmann wrote:
> Hi,
> 
> I use apm on my T30. I added the cpufreq module to the kernel to reduce
> the speed of the cpu. But I still hardly get 2 hours of battery time.
> 
> I wonder if the cpu power management and throttling controll of the cpu
> would consume less enery?
> 
> Is it possible to run apm and acpi at the same time, apm for suspend and
> acpi for cpu controll?

No, only APM or ACPI, not both.

But: you don't need ACPI to lower the CPU frequency. On my A30 with a PIII
processor, running a vanilla kernel with the cpufreq patch and APM
support, I can just do

echo `cat /proc/sys/cpu/0/speed-min` >/proc/sys/cpu/0/speed

to set the CPU speed to the lowest possible value. This will result in
approx. 20% longer battery time.

-- 
tino.keitel@innominate.com
dipl.-inf.                        Innominate Security Technologies AG
software engineer                                   networking people
tel: +49.30.6392-3308                      http://www.innominate.com/