systemd-suspend.service - Man Page

systemd-suspend​.service is a system service that is pulled in by suspend​.target and is responsible for the actual system suspend​. Similarly, systemd-hibernate​.service is pulled in by hibernate​.target to execute the actual hibernation​. Finally, systemd-hybrid-sleep​.service is pulled in by hybrid-sleep​.target to execute hybrid hibernation with system suspend and pulled in by suspend-then-hibernate​.target to execute system suspend with a timeout that will activate hibernate later​.

Immediately before entering system suspend and/or hibernation systemd-suspend​.service (and the other mentioned units, respectively) will run all executables in /usr/lib/systemd/system-sleep/ and pass two arguments to them​. The first argument will be "pre", the second either "suspend", "hibernate", "hybrid-sleep", or "suspend-then-hibernate" depending on the chosen action​. An environment variable called "SYSTEMD_SLEEP_ACTION" will be set and contain the sleep action that is processing​. This is primarily helpful for "suspend-then-hibernate" where the value of the variable will be "suspend", "hibernate", or "suspend-after-failed-hibernate" in cases where hibernation has failed​. Immediately after leaving system suspend and/or hibernation the same executables are run, but the first argument is now "post"​. All executables in this directory are executed in parallel, and execution of the action is not continued until all executables have finished​. Note that user​.slice will be frozen while the executables are running, so they should not attempt to communicate with any user services expecting a reply​.

Note that scripts or binaries dropped in /usr/lib/systemd/system-sleep/ are intended for local use only and should be considered hacks​. If applications want to react to system suspend/hibernation and resume, they should rather use the Inhibitor Locks​^[1]​.

Note that systemd-suspend​.service, systemd-hibernate​.service, systemd-hybrid-sleep​.service, and systemd-suspend-then-hibernate​.service should never be executed directly​. Instead, trigger system sleep with a command such as systemctl suspend or systemctl hibernate​.

Internally, this service will echo a string like "mem" into /sys/power/state, to trigger the actual system suspend​. What exactly is written where can be configured in the [Sleep] section of /etc/systemd/sleep​.conf or a sleep​.conf​.d file​. See systemd-sleep.conf(5)​.

Note that by default these services freeze user​.slice while they run​. This prevents the execution of any process in any of the user sessions while the system is entering into and resuming from sleep​. Thus, this prevents the hooks in /usr/lib/systemd/system-sleep/, or any other process for that matter, from communicating with any user session process during sleep​.

systemd-sleep understands the following commands:

-h,  --help

Print a short help text and exit​.

--version

Print a short version string and exit​.

suspend,  hibernate,  suspend-then-hibernate,  hybrid-sleep

Suspend, hibernate, suspend then hibernate, or put the system to hybrid sleep​.

Added in version 203​.

systemd-sleep.conf(5), systemd(1), systemctl(1), systemd.special(7), systemd-halt.service(8)

1.

Inhibitor Locks
https://systemd.io/INHIBITOR_LOCKS

systemd.directives(7), systemd.index(7), systemd-poweroff.service(8), systemd-sleep.conf(5), systemd-soft-reboot.service(8).

The man pages systemd-hibernate.service(8), systemd-hybrid-sleep.service(8), systemd-sleep(8) and systemd-suspend-then-hibernate.service(8) are aliases of systemd-suspend.service(8).