rtcidle

rtcidle is a daemon that monitors the user activity and place the computer in a suspended (sleep) state after a period of inactivity. At the moment, only PS/2 keyboards and mice and serial mice are monitored, USB input devices are missing.

The features of rtcidle are:

• program the real time clock (RTC) to wake the computer up two minutes before the next scheduled job in the at or cron spool;
• do not sleep if some programs are running; this includes for example cdrecord, as cd-writing should not be interrupted by suspension.

Installation

1. get the sources from the download page and compile;
2. copy rtcidle.conf to /etc; add every program you don't want to be interrupted by suspension there;
3. if something is to be done before suspension or after wakeup, add to /etc/rtcidle.before and /etc/rtcidle.after (this is something you will probably find out after the first test run, see below)
4. update the crontables: if a scheduled program is expected to take more than a few seconds, launch it using the enclosed program waiting; that is, convert:

   * * * * * /path/to/program arguments
   

   to:

   * * * * * /path/to/waiting /path/to/program arguments
   

5. remember to do the same for at jobs
6. run rtcidle

Customization

Some customization of the /etc files may be required to make everything run fine through a suspension. For testing, you can use rtcidle -i, which makes the system going into suspended mode immediately, without waiting for user inactivity. This way, you can then immediately wake the computer up to check whether it is fully operational after the sleep. Note that the -i flag only changes the behaviour at the beginning: when the system wakes up, it again waits for user inactivity before sleeping again.

rtcidle reads /etc/rtcidle.conf before suspending. This is a list of program names. If any of these programs is running, suspension is not entered. At a minimum, waiting and CD-writing programs should be there. Other programs you may not want to be interrupted are backup scripts, etc.

Some kernel modules and/or userspace daemons do not behave correctly through a suspension. You may want to stop them in /etc/rtcidle.before and restart them in /etc/rtcidle.after. If the problem only occur occasionally (or after a long suspension), you may alternatively check whether these services still work in /etc/rtcidle.after and restart them otherwise. For example, my computer sometimes looses control of the network interface during a sleep, ending up with a "Disabling IRQ #12" message. I solved the problem by adding the following to /etc/rtcidle.after:

ping -c 3 another_local_computer
if [ "$?" != 0 ];
then
  echo "Restarting network"
  /etc/init.d/network stop

  # remove and reload modules on irq 12
  rmmod ...
  sleep 1
  modprobe ...

  /etc/init.d/network start
fi

Finding out what to stop and restart (or check and restart) may require some tries.

Notes

• not all computers support suspension; not all that do are able to wake up at a programmed time; before running rtcidle I suggest to check whether your computer supports both features: use apmsleep (if you use APM with the old RTC framework; it is part of the apmd package) or rtcwake (ACPI with the new RTC framework, included in util-linux-ng) to check this.
• If your computer enters the sleep state but then does not wake up at the programmed time, a last resort is to program the bios wakeup time using nvram-wakeup; this is probably the least likely to work, as the wake-up feature is designed for a different aim; if it works, it has to be explicitely called in /etc/rtcidle.before; this script is passed as argument the wakeup time, expressed as number of seconds since 1/1/1970.
• rtcidle uses the system time, but the program you use for sleeping may use the hardware clock instead; keep these two synchronized
• Some kernel versions allow both acpi and apm to be active at the same time (this is disabled in recent versions); this configuration didn't work for me: computer entered suspension but then did not wake up no matter what I did (pressing a key, pressing the power-on button, etc.)
• If a suspended computer does not wake up upon key press, try with the power-on button; generally, which events cause suspension to end are specified in the BIOS configuration.
• The rtc module and the rtc-core/rtc-cmos ones appear to be incompatible with each other: if they are both present, the computer may enter sleep state but not wake up at the right time; note that the rtc module may be included in the kernel, in which case it does not show up in the result of lsmod.
• Some computers may enter sleep state but then come out immediately; this may be due to a keyboard interrupt (try sleep 1; apm -s or similar) or to some other event waking up the computer, such as a network packet (check with tcpdump -p); which events wake the computer can usually be configured in the BIOS
• Currently, rtcidle wakes up for every cron or at job, but do not wait for its completion unless the program is launched via waiting. This may or may not the expected behaviour.