systemd-suspend.service, systemd-hibernate.service, systemd-hybrid-sleep.service, systemd-suspend-then-hibernate.service, systemd-sleep — System sleep state logic
systemd-suspend.service is a system
service that is pulled in by
and is responsible for the actual system suspend. Similarly,
systemd-hibernate.service is pulled in by
hibernate.target to execute the actual
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
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
hybrid-sleep", or "
depending on the chosen action. An environment variable called "
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-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 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
systemd-suspend-then-hibernate.service should never be executed directly. Instead,
trigger system sleep with a command such as systemctl suspend or systemctl
Internally, this service will echo a string like
to trigger the actual system suspend. What exactly is written
where can be configured in the [Sleep] section
/etc/systemd/sleep.conf or a
sleep.conf.d file. See
systemd-sleep understands the following commands: