HowTo: Undervolt your notebook CPU for longer battery life

[mister_playboy]

I followed all of your instructions but my Latitude E6400 battery not increased more than half hour. Is it possible to increase more time?

Generally speaking, lowering the CPU temp is the main advantage of undervolting. It won't increase the battery life too much since the CPU doesn't use much power compared to the screen or hard drive... 30 minutes is probably as good as could be expected.

[Uhuu]

Anybody got this working on Karmic?

[tula]

still not working on karmic koala + turion x2 RM processor ?

[zcats]

Undervolting for 9.10 Karmic was as simple as adding the ppa for PHC and installing the kernel 2.6.31-14-generic-phc using synaptic.
BTW I have a Pentium M processor 1.70GHz and previously had acpi-cpufreq.ko in home (separate partition) before I upgraded to karmic
Of course I still needed to determine and set my optimal values and edit your /etc/rc.local file to make permanent. Add this (using your values):-
echo "17:19 14:12 12:18 10:4 8:1 6:1" > /sys/devices/system/cpu/cpu0/cpufreq/phc_controls
exit 0

The 2.6.31-15-generic-phc is not in the phc ppa yet so I am staying with 2.6.31-14-generic-phc (a bit behind on kernel updates, but thats OK

[zcats]

Ermmmm. This is not quite right, sorry!. Please see my other Ubuntu post in
"Undervolting in Karmic on a Pentium M - a Howto".

Use the instructions by Ebsbel and it works on Karmic..

[zcats]

see
http://ohioloco.ubuntuforums.org/sho...42#post8418342

[aldeby]

[QUOTE=asuna;7644198]Ok thanks for all the help
EDIT:
Finally got it to work!

After I downloaded and used PHC Tool

From http://aldeby.org/blog/index.php/lin...ervolting.html:

Thank you asuna for quoting my post.
Although the actual blog page is http://linux.aldeby.org/linux-phc-cpu-undervolting.html

[H.i.M]

I installed the phc kernel by the ppa:linux-phc/ppa.

uname -r
2.6.31-17-generic-phc

Could someone tell me where the phc_controls-file is gone?
Isnt the phc kernel the right one to undervolt?

ls -a /sys/devices/system/cpu/cpu0/cpufreq/
.   affected_cpus     cpuinfo_max_freq  cpuinfo_transition_latency  related_cpus                   scaling_available_governors  scaling_driver    scaling_max_freq  scaling_setspeed
..  cpuinfo_cur_freq  cpuinfo_min_freq  ondemand                    scaling_available_frequencies  scaling_cur_freq             scaling_governor  scaling_min_freq  stats

thanks
h.i.m

[mister_playboy]

Honestly, we really need a new thread for this topic. The instruction in the first post don't work for any recent kernel and most people aren't going to dig through this whole thread to find the answer.

Anybody who knows exactly what they are doing want to start a new one? I will admit I'm not the one to do it...

[Ares Drake]

Honestly, we really need a new thread for this topic. The instruction in the first post don't work for any recent kernel and most people aren't going to dig through this whole thread to find the answer.

Anybody who knows exactly what they are doing want to start a new one? I will admit I'm not the one to do it...

Unfortunately I currently find no time at all for updates in this matter.

If you however want the first post changed, either with a link to a new thread or with new, provided information & guidelines I am more than willing to help!

Greetz
Drake