PowerNow frequency/power switching

From: Rudolf Usselmann (russelmann_at_hotmail.com)
Date: 06/26/05 

Date: Sun, 26 Jun 2005 13:30:56 +0700

Hi !

I am running FC3 x86_64, 2.6.12.1 on a Tyan MB S2895 with dual
Opteron CPUs.

It appears that both the BIOS and the OS support PowerNow.
As the kernel is booting, I get:

powernow-k8: Found 2 AMD Athlon 64 / Opteron processors (version 1.40.2)
powernow-k8: 0 : fid 0xe (2200 MHz), vid 0x2 (1500 mV)
powernow-k8: 1 : fid 0xc (2000 MHz), vid 0x6 (1400 mV)
powernow-k8: 2 : fid 0xa (1800 MHz), vid 0xa (1300 mV)
powernow-k8: 3 : fid 0x2 (1000 MHz), vid 0xe (1200 mV)
cpu_init done, current fid 0xe, vid 0x2
powernow-k8: 0 : fid 0xe (2200 MHz), vid 0x2 (1500 mV)
powernow-k8: 1 : fid 0xc (2000 MHz), vid 0x6 (1400 mV)
powernow-k8: 2 : fid 0xa (1800 MHz), vid 0xa (1300 mV)
powernow-k8: 3 : fid 0x2 (1000 MHz), vid 0xe (1200 mV)
cpu_init done, current fid 0xe, vid 0x2

However, as I look in /proc/acpi/processor/CPU0/info I see:
% more info
processor id: 0
acpi id: 0
bus mastering control: yes
power management: no
throttling control: no
limit interface: no

I would have expected "power management" and "throttling control"
to be "yes".

Basically I would like for the system to automatically reduce CPU
speed when the system is idle .... I can't find any info or guidelines
for kernel configuration and user/system level apps that would give me
a way to throttle the CPUs. Did anybody manage to do this ?
Any pointer/hints appreciated.

Thanks,
rudi
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