Bug#767532: shutdown-at-night: Allow systemd to wake up machines in the morning?

[Petter Reinholdtsen]

I had a closer look, and start to suspect that the rtcwake command is
operating on the same setting as the acpiwakeup() method in the
shutdown-at-night shell script:

# This method might not work if the hardware clock is updated during
# shutdown.  Changing /etc/default/hwclock to list HWCLOCKACCESS=yes
# to disable it.
# Based on <URL: http://www.mythtv.org/wiki/ACPI_Wakeup >
acpiwakeup() {
    wakeuptime="$1"
    if [ -e /sys/class/rtc/rtc0/wakealarm ] ; then
        when=$(whentowakeup $wakeuptime)

        # First reset alarm
        echo 0 > /sys/class/rtc/rtc0/wakealarm
	
        # Next, set it to our selected time
        echo $when > /sys/class/rtc/rtc0/wakealarm
        logger -t shutdown-at-night "scheduled $hostname to turn itself on at $wakeuptime using /sys/class/rtc/rtc0/wakealarm."
        return 0
    else
        return 1
    fi
}

If this is correct, using rtcwake might make this code simpler, but not
add a new way to get the machine to wake up in the morning, which was my
original motivation for creating this issue.

-- 
Happy hacking
Petter Reinholdtsen