I'm running Mandrake 9.2 with a custom built kernel from mandrake-sources
on a Compaq Evo N800c (Pentium 4 Mobile-processor) with acpi compiled in.
The acpi-support is mostly working, I can read temperature-sensors,
battery-status and the fan controls itself relative to the processor-heat,
but I can not get the processor to speed-step. When I try to

echo 1 > /proc/acpi/processor/C000/performance

strace tells me "No such device", and whenever I read the file it shows

[hhg@localhost hhg]$ cat /proc/acpi/processor/C000/performance
state count: 2
active state: P0
*P0: 2200 MHz, 20000 mW, 500 uS
P1: 1200 MHz, 10000 mW, 500 uS
[hhg@localhost hhg]$

Are there anyone here who can give me som help on how to fix this?

Thank you.