[SOLVED]CPU frequency lower when on battery

Aeva · 2010-12-01 00:27:09

Hi!

I've been using Arch for a month or two now, and am running awesome WM with laptop-mode-tools, cpufrequtils and pm-utils for powersaving on my laptop. I've got most of it figured out already, like governor switching and stuff, but there's this one thing that intrigues me.

My CPU frequency range is 800MHz - 1.80GHz, and this works just fine on AC. But whenever i unplug and go on battery, suddenly my "current policy" reports that the frequency should be within 800MHz - 800MHz. This remains the same for the conservative, ondemand and performance governors.

I've been doing some research and thought it had to do with the acpi handler script, so I appended the lines "echo -n $minspeed >$setspeed" and "echo -n $maxspeed >$setspeed" from the AC case statement to the battery case statement, but this hasn't changed anything it appears.

I also tried disabling the laptop-mode and removing it from my rc.conf, and switching to the cpufreq daemon instead, but this was to no avail either.

Is there any way of changing this at all? Or is it simply meant to be like this?

In advance, thank you very much for the help :)

Last edited by Aeva (2010-12-02 21:54:31)

CountDuckula · 2010-12-01 00:41:55

Suggest you might check your power setting modes in BIOS to see if CPU speed under battery power mode is set there.

Aeva · 2010-12-01 06:56:46

In the BIOS I only have the option to enable/disable AMD powernow. If I turn it off it doesn't change anymore, but of course, the powernow-k8 module doesn't load anymore either.

I guess that I'll have to deal with it then, thank you though, it's good to know the cause.

sati · 2010-12-02 18:53:29

Try adding 'processor.ignore_ppc=1' to your kernel boot line in grub.

Aeva · 2010-12-02 21:41:30

Yeah, that fixed it!
Thank you so much! ^^

litemotiv · 2010-12-02 21:52:03

Please mark your thread solved by prepending it to the title Aeva.

Aeva · 2010-12-02 21:54:48

Done.

Arch Linux

#1 2010-12-01 00:27:09

[SOLVED]CPU frequency lower when on battery

#2 2010-12-01 00:41:55

Re: [SOLVED]CPU frequency lower when on battery

#3 2010-12-01 06:56:46

Re: [SOLVED]CPU frequency lower when on battery

#4 2010-12-02 18:53:29

Re: [SOLVED]CPU frequency lower when on battery

#5 2010-12-02 21:41:30

Re: [SOLVED]CPU frequency lower when on battery

#6 2010-12-02 21:52:03

Re: [SOLVED]CPU frequency lower when on battery

#7 2010-12-02 21:54:48

Re: [SOLVED]CPU frequency lower when on battery

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