[ltp] T61: C4 processor state & frequency scaling

[Jens Rutschmann]

Hi all,

on my T61 powertop only lists C0 - C3 states. I read somewhere that the BIOS
makes the C4 state available if the machine is running on battery power but I
cannot confirm this.
/sys/devices/system/cpu/cpu0/cpuidle contains the subdirectories "state1", 
"state2" and "state3" but no "state4".

The power management options in the BIOS are set to "automatic". I am running
linux-2.6.24-rc4 patched with zen-sources and the latest thinkpad_acpi patch
(0.18-20071203).
I also tried a vanilla 2.6.24-rc4 kernel patched with thinkpad_acpi
0.18-20071203 with the same results.

/proc/acpi/processor/CPU0/power lists:
active state:            C0
max_cstate:              C8
bus master activity:     00000000
maximum allowed latency: 2000 usec
states:
     C1:                  type[C1] promotion[--] demotion[--] latency[001]
usage[00000059] duration[00000000000000000000]
     C2:                  type[C2] promotion[--] demotion[--] latency[001]
usage[00001516] duration[00000000000001924489]
     C3:                  type[C3] promotion[--] demotion[--] latency[017]
usage[00167702] duration[00000000002618371826]

powertop highlighted C3 while I created the list, so why is the active state set
to C0 ? I also wonder if C8 as max_cstate is correct.


Another question is about the frequency scaling. Is it normal that a Core2Duo
only supports four / five P-States ?
Powertop reports 2.01Ghz, 2.0Ghz, 1.6Ghz and 800 Mhz. 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies also lists 1.2Ghz


Thanks for any help !

Regards,
Jens