[Pm-utils] [PATCH] Proposal of auto-hibernate feature

[Victor Lowther]

On Fri, 2009-11-20 at 22:21 +0100, Christian Krause wrote:
> Hi,
> 
> Ever since I've started to use my netbook under Linux I've missed
> quite much the feature of "auto-hibernate" which was available in windows:
> 
> In order to save as much battery power as possible Windows did the
> following:
> 
> - after some minutes of inactivity (or closing the LID) the netbook
> was suspended (to RAM)
> 
> - if the user has woken it up during the next 15 minutes, it just
> resumed quickly
> 
> - otherwise it woke up automatically only to fully hibernate now
> 
> By using this process the user didn't had to think about what would
> be the best option to save power or what he must do to prevent that the 
> suspend mode would drain the battery, everything was done completely
> automatically. Especially for only occasional usage of the netbook/laptop
> it was very handy and so the time until the next recharge was quite long. 
> 
> Using hybrid-suspend was not an option, because even if it would enable
> the user to resume after a complete power-loss it does not prevent draining
> the battery...
> 
> 
> I've missed that feature so much, that Ingo van Lil and I have put together
> an extension to pm-utils which implements this feature.
> 
> It is implemented by only one additional file in /usr/lib/pm-utils/sleep.d/ 
> and a configuration file in /etc). Both files are attached to this mail.
> 
> 
> What's your opinion about this idea? 
> Is there a chance to integrate this into the official pm-utils?
> If yes, we would certainly help to achieve this! ;-)

Seems like it would be better to expose this functionality as a sleep
method, not a hook -- no sense in resuming from suspend, waking all the
way back up, figuring out that we just want to go straight back to
hibernate, and then go do that -- the less we do between waking up and
hibernating, the less there is to go wrong.

> Best regards,
> Christian
> 
> /usr/lib/pm-utils/sleep.d/000auto-hibernate:
> 
> #! /bin/sh
> #
> # Copyright 2009 Ingo van Lil <inguin at gmx.de>
> #                Christian Krause <chkr at plauener.de>
> #
> # This program is free software; you can redistribute it and/or modify
> # it under the terms of version 2 of the GNU General Public License as
> # published by the Free Software Foundation.
> 
> . "${PM_FUNCTIONS}"
> 
> # constants
> # how long to wait for the main script to release the lock in seconds
> LOCK_TIMEOUT=10
> 
> # defaults
> RTC="/sys/class/rtc/rtc0"
> TIME_TO_HIBERNATE=900
> 
> # get user configured values
> source /etc/pm-utils-auto-hibernate.conf
> 
> # Is auto-hibernate enabled ?
> [ "$AUTO_HIBERNATE_ENABLED" = "y" ] || exit $NA
> 
> schedule_alarm () {
> 	now=`cat "${RTC}/since_epoch"`
> 	alarm_time=$((now + TIME_TO_HIBERNATE))
> 	savestate auto-hibernate-alarm ${alarm_time}
> 	echo > "${RTC}/wakealarm"
> 	echo ${alarm_time} > "${RTC}/wakealarm"
> }
> 
> schedule_hibernate () {
> 	# wait for pm-action to terminate ...
> 	spin_lock "${STASHNAME}.lock" ${LOCK_TIMEOUT} || exit 1
> 	release_lock "${STASHNAME}.lock"
> 	# ... before hibernating
> 	pm-hibernate
> }
> 
> auto_hibernate () {
> 	now=`cat "${RTC}/since_epoch"`
> 	wakealarm=`cat "${RTC}/wakealarm"`
> 	alarm_time=`restorestate auto-hibernate-alarm`
> 	if [ -n "${alarm_time}" ]; then
> 		if [ ${now} -ge ${alarm_time} -a ${now} -lt $((alarm_time + 30)) ]; then
> 			echo "Woken up by RTC, auto-hibernating ..."
> 			schedule_hibernate &
> 		elif [ "${alarm_time}" = "${wakealarm}" ]; then
> 			# cancel alarm
> 			echo > "${RTC}/wakealarm"
> 		fi
> 	fi
> }
> 
> case $1 in
> 	suspend) schedule_alarm ;;
> 	resume) auto_hibernate ;;
> 	help) help ;;
> 	*) exit $NA ;;
> esac
> 
> 
> /etc/pm-utils-auto-hibernate.conf:
> 
> # RTC="/sys/class/rtc/rtc0"
> TIME_TO_HIBERNATE=30
> AUTO_HIBERNATE_ENABLED=y
> 
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