gistfile1.sh

#! /bin/sh
# Refactored from Ubuntu's hdparm script

# It isn't safe to set an APM policy by default on Firewire or USB devices.
# See https://bugs.launchpad.net/bugs/515023.
has_apm()
{
    hdparm -i $dev 2> /dev/null | grep -q 'AdvancedPM=yes'
}

hdparm_is_on_battery() {
    on_ac_power 2>/dev/null
    [ $? -eq 1 ]
}

cancel_hdparm_apm()
{
  for dev in /dev/sd? /dev/hd? ; do
		if [ -b $dev ] && has_apm $dev ; then
			hdparm -B 254 $dev
			hdparm -S 0 $dev
		fi
	done
}

start_hdparm_apm()
{
	for dev in /dev/sd? /dev/hd? ; do
		if [ -b $dev ] && has_apm $dev ; then
			hdparm -B 1 $dev
			hdparm -S 24 $dev
		fi
	done
}

resume_hdparm_apm()
{
	if hdparm_is_on_battery ; then
		start_hdparm_apm
	else
		cancel_hdparm_apm
	fi
}

case "$1" in
	true) #powersaving on
		resume_hdparm_apm
		;;
	false) # powersaving off
		cancel_hdparm_apm
		;;
	thaw|resume|post) # resume pm
		resume_hdparm_apm
		;;
	*)
		exit 254
		;;
esac