#!/bin/sh
#
# start of stop laptop mode, best run by a power management daemon when
# ac gets connected/disconnected from a laptop
#
# FIXME: assumes HZ == 100

# age time, in seconds. should be put into a sysconfig file
MAX_AGE=600

# kernel default dirty buffer age
DEF_AGE=30
DEF_UPDATE=5

if [ ! -e /proc/sys/vm/laptop_mode ]; then
	echo "Kernel is not patched with laptop_mode patch."
	exit 1
fi

if [ ! -w /proc/sys/vm/laptop_mode ]; then
	echo "You do not have enough privileges to enable laptop mode."
	exit 1
fi

case "$1" in
	start)
		AGE=$((100*$MAX_AGE))
		echo -n "Starting laptop mode"
		echo "1" > /proc/sys/vm/laptop_mode
		echo "$AGE" > /proc/sys/vm/dirty_expire_centisecs
		echo "$AGE" > /proc/sys/vm/dirty_writeback_centisecs
		echo "."
		;;
	stop)
		U_AGE=$((100*$DEF_UPDATE))
		B_AGE=$((100*$DEF_AGE))
		echo -n "Stopping laptop mode"
		echo "0" > /proc/sys/vm/laptop_mode
		echo "$B_AGE" > /proc/sys/vm/dirty_writeback_centisecs
		echo "$U_AGE" > /proc/sys/vm/dirty_expire_centisecs
		echo "."
		;;
	*)
		echo "$0 {start|stop}"
		;;

esac

exit 0