Schedule ACPI wakeup script

schedule_acpi_wakeup.sh

#!/bin/sh
#
# Schedule ACPI wakeup
#
# Author: Laurynas Butkus (laurynas.butkus at gmail.com)
#
# Some info on ACPI wakeup:
# http://smackerelofopinion.blogspot.com/2009/08/acpi-wake-alarm-bugs.html
#

#SLEEP_SECS=19*60*60
#SECS=$((`cat /sys/class/rtc/rtc0/since_epoch`+$SLEEP_SECS))

SECS=$((`date --date '00:00 tomorrow'  +'%s'`))
MIN_SLEEP_SECS=$((30*60))
REMAIN=$(($SECS-`date +'%s'`))

# check if will sleep minimum sleep time
if [ $REMAIN -le $MIN_SLEEP_SECS ]; then
    echo "Wakeup time too close. Adjusting sleep time."
    SECS=$((`date +'%s'` + $MIN_SLEEP_SECS))
fi

REMAIN_M=$((($SECS-`date +'%s'`)/60))

#echo $SECS
echo "Will sleep for $REMAIN_M minutes"

echo 0 > /sys/class/rtc/rtc0/wakealarm
echo $SECS > /sys/class/rtc/rtc0/wakealarm