Optimizing Laptop Battery Life on Linux
 

So I've come across several tips to optimize battery life on Linux. Anyone else have any ideas?

http://www.friedbeef.com/top-15-ways...-battery-life/
http://www.lesswatts.org/projects/powertop/
http://lifehacker.com/398622/ramlog-...ard-drive-life
http://www.batteryuniversity.com/
http://ubuntuforums.org/showthread.php?t=786402

In addition to undervolting, I would like to underclock. Is there a way to control CPU speed outside of the BIOS via some software control in Linux... or some sort of boot manager? I would like to boot to linux using underclocked speeds and have Windows running full blast.

Last point: Is there a way to run Linux completely in RAM? I have read that saves on power consumption from the hard drive.

I've run a live cd in RAM. I believe I was using Slax (slackware derivative) and at the bootup, ran the command
That may work on other distros, not sure though.
Also, the distro DreamLinux has a button in the gui called 'quiet and cool' that slows the system down, using less power. It is also a live cd, but this function will work in a HardDrive install.

Ahh interesting... I looked it up and apparently the Quiet and Cool feature is only available on AMD chips, so I'm out of luck there. :/

You can use kernel "cpufreq" features and many more things.
One good tutorial: http://www.gentoo.org/doc/en/power-management-guide.xml
I guess you can run it from USB flash drive. I personally don't use swapping, but not for powersaving, I am not even sure it really helps to save battery time, it just speeds up things.

From other site on amd.
"Kernel 2.6
If you're running a 2.6 kernel (check uname -a), you need to have cpu frequency scaling enabled. Check this by doing:

grep CPUFREQ /usr/src/linux-2.6.x/.config
It should return CONFIG_X86_ACPI_CPUFREQ=y or CONFIG_X86_ACPI_CPUFREQ=m.
To be able to control the cpu frequency from userspace, you should also choose USERSPACE as the cpu frequency governor:

grep USERSPACE /usr/src/linux-2.6.x/.config
# CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set
CONFIG_CPU_FREQ_GOV_USERSPACE=y
Then you can use the cpufreq interface in /sys/ to change the speed:

cd /sys/devices/system/cpu/cpu0/cpufreq/
There you will find some files. You can control the cpu frequency by echoing a value in kHz to the file scaling_setspeed:

echo 600000 > scaling_setspeed
This will set your cpu to 600MHz.

You can also install a userspace daemon to dynamically change the cpu speed according to your power/acpi status and performance needs: cpufrqd, speedfreqd. "


Not sure if you can in linux but acpi is a far reaching spec that can if enabled in hardware control very finely each part of a system. It can turn off power to a part like modem or pcmcia or even bridge to bridge.

The best solution may be to lower backlight. It may be one of the biggest users or power. There usually is a hot key that may or may not be known. I know ibm's used to be something like alt-b or some key combo like that.