Odd power management on ThinkPad T43

[Nate Lawson]

Kevin Oberman wrote:
> I'm running current on an IBM ThinkPad T43 and I'm not sure I have a problem, 
> but something odd seems to be going on.
> 
> I have a 2.0 GHz Pentium-M which I believe is 760. I believe it's one IBM has 
> not released information on the EST specs.
> 
> If I do NOT have cpufreq loaded, I see:
> dev.cpu.0.freq_levels: 2000/27000 1750/23625 1600/22600 1400/19775 1333/19666 
> 1166/17207 1066/16733 932/14641 800/13800 700/12075 600/10350 500/8625 
> 400/6900 300/5175 200/3450 100/1725
> 
> If I load cpufreq I see:
> dev.cpu.0.freq_levels: 1500/-1 1312/-1 1200/-1 1050/-1 1000/-1 875/-1 800/-1 
> 700/-1 600/-1 525/-1 450/-1 375/-1 300/-1 225/-1 150/-1 75/-1
> 
> With cpufreq I report perf0, est0 and p4tcc0 in dmesg. Without loading cpufreq 
> I still see acpi_perf0 and acpi_throttle0.
> 
> This would lead me to believe that without cpufreq I am only seeing 
> throttling, but I see my clock speed decrease (x86info) which I did not expect 
> to see with pure throttling.
> 
> Am I better off when on battery to use cpufreq or not? Is there something to 
> tweak to get full 2GHz performance with EST?

This sounds like a bad table match for est0.  Perhaps it's detecting 
your CPU as a 1.5Ghz one when it's actually 2Ghz.

An easy way to tell is to load cpufreq but disable just est with:
hint.est.0.disabled="1"

You should get acpi_perf and p4tcc, and the frequencies will be correct 
for your system.  acpi_perf is often more user-friendly anyway since it 
reports the power consumed at each level instead of just "-1".

It's also possible you were booting on battery and had lower levels 
available.  Easy way to tell is report output of sysctl -a | grep cpu

-- 
Nate