Entries in Life

When I saw Harald Sitter’s post about longer battery life on Linux, I decided to give it a try. Especially since, at the time, he hadn't posted his script.

Here is what I came up with:

#!/bin/sh

# powertop says beagle takes up a lot of power
killall beagled

###############################################
# http://www.lesswatts.org/tips/disks.php
# Disks!
###############################################

# I don't need no stinkin' atime
sudo mount -o remount,noatime /

# Laptop mode works by submitting all future pending disk IO (such as
# pending VM cache writebacks as described in the VM writeback time tip)
# at once when the kernel has to do an IO to the disk for any reason
sudo sh -c 'echo 5 > /proc/sys/vm/laptop_mode'

# Only write to disk every 15s - we have a battery and few crashes. 
sudo sh -c 'echo 1500 > /proc/sys/vm/dirty_writeback_centisecs'

# Turn on power management after 1 minute
for i in `echo /dev/sd?`; do
    [ -e $i ] && sudo hdparm -B 1 -S 12 $i
done

# Turn off cdrom polling
for i in `echo /dev/scd?`; do
    [ -e $i ] && sudo hal-disable-polling --device $i
done

###############################################
# http://www.lesswatts.org/tips/wireless.php
# Wireless!
###############################################

# WiFi power saving
sudo iwpriv eth1 set_power 5

# turn off bluetooth
sudo /etc/init.d/bluetooth stop
sudo modprobe -r rfcomm
sudo modprobe -r l2cap
sudo modprobe -r bluetooth

###############################################
# http://www.lesswatts.org/tips/cpu.php
# CPU!
###############################################

# Enable the power-aware SMP scheduler
sudo sh -c 'echo 1 > /sys/devices/system/cpu/sched_mc_power_savings'

###############################################
# http://www.lesswatts.org/tips/ethernet.php
# Ethernet!
###############################################

# turn off gigabit ethernet
sudo ethtool -s eth0 autoneg off speed 100

# turn of WOL
sudo ethtool -s eth0 wol d

###############################################
# http://www.lesswatts.org/tips/graphics.php
# Graphics/Video!
###############################################

# turn the LCD backlight down to 12%
# I found that xbacklight only works for certain values on my x60
xbacklight -set 12

# Turn off screen aff after 2minutes
xset +dpms
xset dpms 0 0 120

###############################################
# http://www.lesswatts.org/tips/misc.php
# Misc!
###############################################

# Turn on audio power saving
if [ -e /sys/module/snd_hda_intel/parameters/power_save ]; then
    sudo sh -c 'echo 10 > /sys/module/snd_hda_intel/parameters/power_save'
fi

if [ -e /sys/module/snd_ac97_codec/parameters/power_save ]; then
   sudo sh -c 'echo 1 > /sys/module/snd_ac97_codec/parameters/power_save'
   sudo sh -c 'echo 1 > /dev/dsp'
fi

Of course, you'll want something to turn everything back on when you get back on power:

#!/bin/sh

# Turn Beagle back on!
beagled&

# Turn off wifi powersaving
sudo iwpriv eth1 set_power 6

# Write to disk more often
sudo sh -c 'echo 300 > /proc/sys/vm/dirty_writeback_centisecs'

# Disable the power-aware SMP scheduler
sudo sh -c 'echo 0 > /sys/devices/system/cpu/sched_mc_power_savings'

# turn on bluetooth
sudo modprobe bluetooth
sudo /etc/init.d/bluetooth start

# turn on gigabit ethernet
sudo ethtool -s eth0 autoneg on speed 100

# turn the LCD backlight up
xbacklight -set 100

# Turn off screen aff after 30 minutes
xset +dpms
xset dpms 0 0 1800

# Turn on cdrom polling
for i in `echo /dev/scd?`; do
    [ -e $i ] && sudo hal-enable-polling --device $i
done

Note that I don't reverse every step in my power-saving script. Just most of them.