How to lower power consumption

I'm using Linux on my IBM X31 from the first day on I got it 3 years ago. But for some coding things I still have Windows on it. A few weeks ago I tried Notebook Hardware Control to undervolt the notebook under Windows and thrilled about the effect, so I searched for similar possibilities with Linux. I found the PHC Patch and tried it. It worked well but I wondered why I couldn't get the power conspumption as low as I got it under Windows.
Of coure I tried a lot of things (removing almost every kernel module for example) but still I won't go under 11 Watt of consumption with Linux (darkest screen setting, wifi off) while I got between 7 and 8 Watt with Windows (also darkest screen setting, wifi off).

Now I wonder if anyone knows a way to lower the consumption with linux, because that a big amount of mobile time I'm loosing (more than 1 hour with ne normal battery and even more with the additional battery pack).

 

sorry i dont know what GPU your X31 has, but perhaps your GPU is using the extra power.....
Are you using some sort of (xgl GUI i think its called), like Beryl??

You might need to have a fiddle with ACPI under linux, perhaps its not enabled properly. My friend had to modify quite a few files to get it all working...

insane

 

The X31 has an Radeon M6 (Radeon 7000) videochip. I'm not using any special windowmanager (normal metacity/gnome) and i'm using the dynamic clocking for the videochip. As far as I can see all acpi stuff works normal, I can read all hotkey events through acpi, can suspend to disk or ram and read out all kind of information. So I guess it works. Maybe the code itself isn't as efficient but I don't really believe it. Something must be wrong.

 

could it be the harddrive? I know in my Ubuntu 6.10 install there is a "laptop-mode" service that supposedly reduces hard disk activity while on batteries.

 

That's a good question. I'll try to shut the HDD down and take a look at the resulting consumption.

 

I don't use a ubuntu flavour of linux, but with recent kernels laptop-mode is built-in

Check the state by
$ cat /proc/sys/vm/laptop_mode
0

0 means disabled. Enable by:
$ echo 1 >> /proc/sys/vm/laptop_mode

laptop mode works by 'clustering' disk accesses, so reads and writes don't happen until there is a significant amount of stuff to do. It doesn't actually spin down your drives though, you will still need to 'hdparm' to set the spin-down time to some nice small number. Together, you can greatly reduce HDD power consumption without any noticeable impact. One warning -> I have heard lots of spin-ups spin-downs of the HDD can reduce its life.

 

There is a Debian package that makes setting laptop-mode and hdparm into a no-brainer. http://www.samwel.tk/laptop_mode/tools/index.html