[ltp] PM on Thinkpad T41

[Stephan Frank]

Hallo Micha,

On Wed, 31 Mar 2004, Micha Holzmann wrote:
[snip]
> in /sys/devices/system/cpu/cpu0/cpufreq/
>
> for i in *; do echo $i:; cat $i; done
> cpuinfo_max_freq:
> 1400000
> cpuinfo_min_freq:
> 600000
> scaling_available_governors:
> userspace powersave performance
> scaling_driver:
> centrino
> scaling_governor:
> powersave
> scaling_max_freq:
> 600000
> scaling_min_freq:
> 600000
>
> The /proc/cpuinfo still tell me the frequency ist on 1395 MHz:
>
> grep -Ei "^cpu mhz" /proc/cpuinfo
> cpu MHz         : 1395.486
>
> > restart and you go on...
>
> Yes i did, but with no effects.

try as root:

echo "userspace" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo "600000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

a 'cat /proc/cpuinfo' should now show a cpu Mhz of around 600.

you should use the powernowd which does a good job of stepping to
different frequencies (automatically) depending on the cpu load.
(yes, despite its name it also works for architectures other than AMD
processors.)

This works quite nice on my R50 and enahnces battery runtime a lot,
however the fan still kicks in after some time (at around 38=B0C
temperature) and never shuts off again even  when the temperature is again
at around 30=B0C.

I was not able to solve this problem, though have seen several
posts/descriptions of people having the same problem. It seems people
believe it is a BIOS related bug or a buggy DSDT code. If someone knows a
solution to the fan problem I would also be glad to hear about it.

I hope this was helpful.

Kind regards,
Stephan