HowTo: Undervolt your notebook CPU for longer battery life

[easytool]

Can someone post a 64bit apci-cpufreq.ko for kernel 2.6.27-7 ? 64bit please~~

I tried to compiled it for a whole night, but couldnot work it out.

Many Thanks!!!

[coolen]

This sounds great.

One thing I'm wondering, though: when on AC, can I automatically switch to a higher voltage? I don't particularly mind about heat: the cooling on this laptop is fantastic. If I'm on AC anyway, I want to get the most out of my CPU.

Is there a way to do this?

[sarah.fauzia]

I'm running latest intrepid kernel (2.6.27-5-generic) succesfully with the phc extensions, and also was running 2.6.27-4-generic.

How I did? First I moved the acpi-cpufreq.ko original module to acpi-cpufreq.ko-original, then installed the linux-phc package from here http://ppa.launchpad.net/bonniot-use...n/l/linux-phc/ and rebooted.

After rebooting you can run sudo linux-phc-install and reboot, it should work fine. After that I removed the linux-phc package, since it seemed to give out an error when installed.

If I didn't move the acpi-cpufreq.ko module out of the way it gave me an error.

Hope it helps

With linux kernel 2.6.27-7 in 64-bit Intrepid still gives me an error, and I've been unsuccessful in compiling... I went through all the steps prior to the reboot without any errors, and when I run

cat /sys/devices/system/cpu/cpu0/cpufreq/phc_controls

I get:

cat: /sys/devices/system/cpu/cpu0/cpufreq/phc_controls: No such file or directory

Also, when I enter

lsmod | grep acpi_cpufreq

Nothing happens. It just gives another blank prompt, as if I hadn't asked for anything.

But when I restore the backup copy and reboot, I get normal values again.

By the way, I'm using an Lenovo X61T with the latest release of Intrepid (kernel 2.6.27-7).

[pardes3]

I also tried to compile it on 64 bit but was not successful. Anyone here have ahd success yet? If so, please post the compiled version for us.

Thanks!!!

[landal]

The compilation on a 64bit system works well with this how-to : http://wiki.ubuntuusers.de/Prozessorspannung_absenken (link on the first post)

command isn't the same as in this forum. This works :

cd arch/x86/kernel/cpu/cpufreq/
make -C /lib/modules/$(uname -r)/build SUBDIRS=$(pwd) modules

And I post the result.

[pardes3]

The compilation on a 64bit system works well with this how-to : http://wiki.ubuntuusers.de/Prozessorspannung_absenken (link on the first post)

command isn't the same as in this forum. This works :

cd arch/x86/kernel/cpu/cpufreq/
make -C /lib/modules/$(uname -r)/build SUBDIRS=$(pwd) modules

And I post the result.

Sir, very kind of you. Thanks!

[quirks]

I couldn't find the compiled module for the latest Hardy kernel (2.6.24-21-generic), so I compiled it myself. Here it is:

[pardes3]

I am not sure why when I run the optimize script... it starts and goes all the way to -1 and stops. It throws line 161 printf error and says 0 is lowest VID, run the test again. But if I run again it complains about WRONG VID COUNT.

Help?

Thanks

[knix]

I am not sure why when I run the optimize script... it starts and goes all the way to -1 and stops. It throws line 161 printf error and says 0 is lowest VID, run the test again. But if I run again it complains about WRONG VID COUNT.

Help?

Thanks

honestly how i finally did it was use RMclock in windows xp to find the best voltage, then translated it into the vids i got from the script (i wrote them down)

[sarah.fauzia]

Well, the compiled module for 64-bit works, but I think my case might be unique...

cat /sys/devices/system/cpu/cpu0/cpufreq/phc_controls
10:36 9:25 6:21 136:11

I get a VID for my first frequency of 0. I took the precaution and used 1 instead. However, when I echo it, my computer freezes, and when I added it to my startup in /etc/rc.local, my computer becomes unbootable and the screen strangely dark (though I connected it to the AC). Removing it from /etc/rc.local with the root terminal fixes the problem (though I was scared for a few minutes there!) Does that mean I can't undervolt my processor?

I have a Lenovo X61T, running Ubuntu Intrepid, 64-bit.