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Re: Power saving techniques


On  18 Mar, this message from T. M. echoed through cyberspace:
> 1) Does my PowerBook support cpu scaling? How do I enable it? Can I  
> even make it run at 500Mhz or so?

It most probably does. As was already said, your kernel needs to support
cpufreq scaling. I recommend userspace governor together with powernowd
(don't be fooled by it's name). powernowd is extremely simple and very
good at what it was designed for: scale cpufreq according to computing

To check, may I recommend the cpufreq applet under Gnome (or the
equivalent under KDE).

> 3) How do I make my hard disk sleep?

Get laptop-mode. That's a kernel functionality (was a patch, but should
be available by default these days) together with user-space tools.

You may tune the defaults file in Debian a bit

Other than what you already know, backlight is a big power eater. Turn
backlight down whenever you can. Configure pbbuttonsd to do that when
there is no activity.

Then, keep an eye on your battery health. Check how your battery's
maximum charge decreases over time, when you accumulate charge cycles.
You can check in /proc/pmu/battery_0.

When it goes down, you can try to recalibrate your battery: let the
computer run until the battery shuts it down, with no pmud or pbbuttonsd
running to keep you from doing that. Preferably, do that with all
documents saved, and the filesystems mounted read-only (if you can).



Michel Lanners                 |  " Read Philosophy.  Study Art.
23, Rue Paul Henkes            |    Ask Questions.  Make Mistakes.
L-1710 Luxembourg              |
email   mlan@cpu.lu            |
http://www.cpu.lu/~mlan        |                     Learn Always. "

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