CPU - Power state (Cx) usage count not working

Gerfried Maier
2006-01-23T08:19:52Z

Hi everybody!

According to the ACPI4Linux doc

cat /proc/acpi/processor/CPU0/power

should look like

active state: C2
default state: C1
bus master activity: 00004f00
states:
C1: promotion[C2] demotion[--] latency[000]
usage[00033670]
*C2: promotion[C3] demotion[C1] latency[084]
usage[00357060]
C3: promotion[--] demotion[C2] latency[120]
usage[00000000]

Unfortunaltely on my system (P4m 1800Mhz; 2.4.31 or .32) the usage count
shows always 00000000. Unloading several modules (eg usb-ohci) has no
effect.

IIrc the count and the statistics were working in earlier times (arond
2.4.25+) All of them vanilla with the preemptive patch from
http://www.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/v2.4/

Is there anything I can do to figure out more on the reason?
Of course I would like to know whether this is only a symptom for a
minor proble or wheher the whole power-state thing is not working,
resulting in shorter battery life.

Thanks for your help!

G. Maier