ACPI action script for battery events

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This is an example ACPI action script that makes Power Management adjustments according to if you are on battery or on AC. Usually this is saved as /etc/acpid/actions/

# Tried on Gentoo
# cpu throttling is in here it is the cpufreq-set lines
# turning swap off is only for those that feel comfortable
# doing something this nasty.
# comment out the laptop_mode line if you don't have it installed
# pcfe, 2008-10-28

# spindown time for HD (man hdparm for valid values)
# I prefer 2 hours for acad and 2 min for batt
# Power management level
# 255 (off) on AC
# 128 (medium) on batt
# lowered to 32, pcfe, 2004-06-23
# upped to 64, pcfe, 2004-07-14
# upped to 96, pcfe, 2004-10-20
# ac/battery event handler
status=`awk '/^state: / { print $2 }' /proc/acpi/ac_adapter/AC/state`
if [ "$status" = "off-line" ]
              logger "Running /sbin/laptop_mode start"
              /sbin/laptop_mode start
              logger "Setting HD spindown for BATT mode with hdparm -S $BATT_HD /dev/hda."
              /sbin/hdparm -S $BATT_HD /dev/hda > /dev/null 2>&1
              logger "Setting HD powersaving for BATT mode with hdparm -B $BATT_PM /dev/hda."
              /sbin/hdparm -B $BATT_PM /dev/hda > /dev/null 2>&1
              logger "Turning off swap."
              /sbin/swapoff -a
	       /usr/bin/cpufreq-set -g conservative         
              logger "Turning on swap."
              /sbin/swapon -a
              logger "Running /sbin/laptop_mode start"
              /sbin/laptop_mode stop
              logger "Setting HD spindown for AC mode with hdparm -S $ACAD_HD /dev/hda."
              /sbin/hdparm -S $ACAD_HD /dev/hda > /dev/null 2>&1
              logger "Setting HD powersaving for AC mode with hdparm -B $ACAD_PM /dev/hda."
              /sbin/hdparm -B $ACAD_PM /dev/hda > /dev/null 2>&1
              /usr/bin/cpufreq-set -g ondemand

On archlinux you might need to add an event like a file e.g. saved as /etc/acpi/events/battery_event with following lines in it:


Note also on archlinux the acpi actions and events are located in /etc/acpi (not /etc/acpid as in gentoo)

After restarting your acpi daemon the script should be activated on switching the power supply on/off. You could check your logs to be sure that everything works as expected.