• Registered: 2009-05-04
  • Posts: 250

Topic: Undervolting on Statler

I'm sure there are others around that are as miserly with their power as I am, so thought I'd share a few links that made it pretty easy to setup undervolting on Intel chips.  I'm on an Intel Core Duo, although this should also work for Pentium M class chips and Intel Core 2 Duos (and perhaps more.)

Linux-phc in Liquorix
First things first is to somehow get linux-phc (http://www.linux-phc.org/) into your kernel. You can patch your own kernel (their website has guides) though I've had easier success with pre-compiled kernels including it by Liquorix (http://liquorix.net/). I favor this cause it has a number of desktop-machine tweaks plus a few other helpful additions for Thinkpads. There is an authenticated repository for debian systems available. It is based of the Zen kernel, which include all kinds of interesting extras you can check out at http://zen-kernel.org/included-code.

To add and install Liquorix:

  • Update and install: sudo apt-get update && sudo apt-get install liquorix-keyring linux-image-2.6-liquorix-686

  • Reboot, making sure to select Liquorix kernel at boot (if it isn't auto selected)

Undervolting
Over at the Debian forums oOarthurOo has already written a very detailed guide on how to set your new voltage values, as well as providing scripts for automatically changes them on startup (/etc/init.d script), and when coming out of sleep (sleep.d hook). No point in relaying every step as his guide does a very nice job. You can check it out at  http://o0arthur0o.wordpress.com/2010/06 … n-squeeze/ .

.

  • Remember that you'll need to edit the values in these scripts to match your own voltages. It basically comes down to how low you can go without you system throwing up errors. It will eventually...my only when nuts when I echo'd in the lowest possible values for all states. I'd highly recommend testing values by manually echo'ing them in, rather than by putting them in the script. Else, if you set them too low, you might get errors just booting.

G'luck.

Last edited by jmbarnes (2010-08-05 20:33:16)

IRC: PizzaAndWine     Script bits: Incremental Backup | Sleep Timer
  • From: forest town, lake land
  • Registered: 2011-02-26
  • Posts: 358

Re: Undervolting on Statler

I couldn't get the scripts in the linked tutorial to work, so I did things a bit differently. I am using the liquorix kernel as well. I put my values instead in /etc/rc.local. As usual make sure you edit this with your own values.

add to your /etc/rc.local

#Enable linux-phc
phc_vids="12:15 10:15 8:15 6:15"
echo "$phc_vids" > /sys/devices/system/cpu/cpu0/cpufreq/phc_controls
echo "$phc_vids" > /sys/devices/system/cpu/cpu1/cpufreq/phc_controls

My 93linux-phc script is a bit different as well. I placed it in /etc/pm/sleep.d, makes for easier backing up.

/etc/pm/sleep.d/93linux-phc

#!/bin/sh

phc_vids="12:15 10:15 8:15 6:15"

case $1 in
    resume|thaw)
        echo "$phc_vids" > /sys/devices/system/cpu/cpu0/cpufreq/phc_controls
        echo "$phc_vids" > /sys/devices/system/cpu/cpu1/cpufreq/phc_controls
        ;;
    suspend|hibernate)
        echo "$phc_vids" > /sys/devices/system/cpu/cpu0/cpufreq/phc_controls
        echo "$phc_vids" > /sys/devices/system/cpu/cpu1/cpufreq/phc_controls
        ;;
esac
Apt Pinning - Pulseaudio - Nvidia Drivers - Laptop Power Saving - 3G Bandwidth Logging -  obmocmenu
  • Registered: 2009-05-04
  • Posts: 250

Re: Undervolting on Statler

Actually just picked up a few refurb thinkpads and had been meaning to do this -- thanks for reminding me.Just applied your method/script to the x60 and all is working well. ACPI temps a bit lower already. Now to apply it to the T60/home server...

The only difference I have is that I've echoed single values (25 21 19) in phc_vids rather than couplets into phc_controls. Any reason for your method?

IRC: PizzaAndWine     Script bits: Incremental Backup | Sleep Timer
  • From: forest town, lake land
  • Registered: 2011-02-26
  • Posts: 358

Re: Undervolting on Statler

jmbarnes wrote:

The only difference I have is that I've echoed single values (25 21 19) in phc_vids rather than couplets into phc_controls. Any reason for your method?

No reason, other than that is the way I have always done it. Using phc_vids or phc_controls will yield the same result.

I'm glad this served as a reminder for you. PHC makes my CPU, an Atom n270,  run about 12C cooler under full load, and about 6C cooler while idle, not to mention a few extra minutes on battery. A worthwhile tweak.

Last edited by hardran3 (2011-03-01 22:46:28)

Apt Pinning - Pulseaudio - Nvidia Drivers - Laptop Power Saving - 3G Bandwidth Logging -  obmocmenu
  • Registered: 2009-05-04
  • Posts: 250

Re: Undervolting on Statler

Good stuff. Before bed I undervolted the t60 which sits in a dock and acts as my main desktop/home server. It ran about 5C cooler overnight.

Perhaps I'll take a few minutes today and wiki-fy your entry. Corenominals inclusion of the Liquorix kernel has made undervolting extremely easy in #!.

IRC: PizzaAndWine     Script bits: Incremental Backup | Sleep Timer
  • From: forest town, lake land
  • Registered: 2011-02-26
  • Posts: 358

Re: Undervolting on Statler

jmbarnes wrote:

Good stuff. Before bed I undervolted the t60 which sits in a dock and acts as my main desktop/home server. It ran about 5C cooler overnight.

Perhaps I'll take a few minutes today and wiki-fy your entry. Corenominals inclusion of the Liquorix kernel has made undervolting extremely easy in #!.

Glad to hear it is working out well. Thinkpads are good machines, the first computer I ran linux on was a R52P.

If you would put it on the wiki that would be great. Another thing to add is to use the newest Liquorix kernel. Using the Liquorix version that is included in crunchbang I was getting a load average of "0.50 0.50 0.50" if I left my machine idle for 15 minutes. The latest kernel from the Liquorix repository under the same circumstances sits at "0.00 0.01 0.05". I haven't done any benchmarking but it seems to be snappier with the 2.6.37 kernel.

Last edited by hardran3 (2011-03-01 22:44:49)

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  • jvd
  • #! CrunchBanger
  • Offline
  • Registered: 2010-01-29
  • Posts: 193

Re: Undervolting on Statler

Not enough summer for me yet to try this out. Family is warming hands cosily 'round a purposely overvolted core  cool

  • From: forest town, lake land
  • Registered: 2011-02-26
  • Posts: 358

Re: Undervolting on Statler

jvd wrote:

Not enough summer for me yet to try this out. Family is warming hands cosily 'round a purposely overvolted core  cool

You need to get a P4 overclocked. Makes a great space heater smile

Last edited by hardran3 (2011-03-01 23:24:30)

Apt Pinning - Pulseaudio - Nvidia Drivers - Laptop Power Saving - 3G Bandwidth Logging -  obmocmenu
  • jvd
  • #! CrunchBanger
  • Offline
  • Registered: 2010-01-29
  • Posts: 193

Re: Undervolting on Statler

Yeah! The P4! If one's neighbors are careful observers of that pear at the ceiling, they can decipher the morse code from switching it off-and-on-and-of-and-on lol

No, seriously... cool stuff jmbarnes... You happen to have any data on power consumption reduction?

  • Registered: 2009-05-04
  • Posts: 250

Re: Undervolting on Statler

jvd wrote:

You happen to have any data on power consumption reduction?

No good power consumption data to speak of -- I too would be interested. Powertop doesn't seem very consistent as of late, and I don't have any hardware to measure wattage draw otherwise.

Most power savings I imagine would be simply as a result of a lower temperatures meaning the fan doesn't have to run as much.


As to the P4's...I had a home server built around one of them. When I realized it was keeping my room warm in a poorly heated apartment in a Minneapolis winter I decided to it was time to separate my heater from my server.

IRC: PizzaAndWine     Script bits: Incremental Backup | Sleep Timer
  • Registered: 2011-07-23
  • Posts: 1

Re: Undervolting on Statler

I consider switching to Linux, particularly to Crunchbang, however my laptop's hellspawn and it's heating an awful lot. I've changed two fans and thermal grease but it'd still heat up to 68C when I'm gaming, granted I'd undervolted it with Rmclock. I was just wondering how do I convert Rmclock settings to that of a Linux standard:
FID: 6.0x VID: 0.9500V
FID: 7.0x VID: 0.9625V
FID: 8.0x VID: 0.9625V
FID: 9.0x VID: 0.9750V
FID: 10.0x VID: 0.9750V
FID: 11.0x VID: 1.0000V
I have a T5600. Pardon my ignorance but I'm learning something new everyday, as do we all.
PS: Nevermind, I undervolted it. Works exactly as under Windows.

Last edited by Ascalia (2011-07-23 17:25:21)