[ltp] PM on Thinkpad T41

[Stephan Frank]

On Thu, 1 Apr 2004, Micha Holzmann wrote:

> Quoting Stephan Frank <sfrank@cs.tu-berlin.de>:
> > 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.
>
> Unfortunately not, it shows still "cpu MHz         : 1395.819"

Hmm, this is weird.

If you shut down every scaling daemon which might be running
(via '/etc/init.d/powernowd stop' etc.; only one should be running
anyway, but I made the mistake of having accidentally run two different
daemons concurrently which gave quite weird scaling behaviour)
and then do a

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

what does the cat print? I dimmly remember that there were some problems
with the Mhz values somewhere in the /proc hierachy being not updated
correctly when scaling was done, but 2.6.4 should be new enough to do this
without problems (I'm using 2.6.5-rc3-mm2 and everything is fine -- apart
from the fan running continously).

Sorry, I'm starting to get a bit baffled and running out of ideas why
this not working for you.

regs,
Stephan