systemd-sleep.conf, sleep.conf.d — Suspend and hibernation configuration file
/etc/systemd/sleep.conf
/etc/systemd/sleep.conf.d/*.conf
/run/systemd/sleep.conf.d/*.conf
/usr/lib/systemd/sleep.conf.d/*.conf
systemd supports three general power-saving modes:
a low-power state where execution of the OS is paused, and complete power loss might result in lost data, and which is fast to enter and exit. This corresponds to suspend, standby, or freeze states as understood by the kernel.
a low-power state where execution of the OS is paused, and complete power loss does not result in lost data, and which might be slow to enter and exit. This corresponds to the hibernation as understood by the kernel.
a low-power state where execution of the OS is paused, which might be slow to enter, and on complete power loss does not result in lost data but might be slower to exit in that case. This mode is called suspend-to-both by the kernel.
Settings in these files determine what strings
will be written to
/sys/power/disk and
/sys/power/state by
systemd-sleep(8)
when
systemd(1)
attempts to suspend or hibernate the machine.
Configuration files are read from directories in
/etc/, /run/, and
/usr/lib/, in order of precedence.
Each configuration file in these configuration directories shall be named in
the style of filename.conf/etc/ override files with the same name in
/run/ and /usr/lib/. Files in
/run/ override files with the same name in
/usr/lib/.
Packages should install their configuration files in
/usr/lib/. Files in /etc/ are
reserved for the local administrator, who may use this logic to override the
configuration files installed by vendor packages. All configuration files
are sorted by their filename in lexicographic order, regardless of which of
the directories they reside in. If multiple files specify the same option,
the entry in the file with the lexicographically latest name will take
precedence. It is recommended to prefix all filenames with a two-digit number
and a dash, to simplify the ordering of the files.
If the administrator wants to disable a configuration file supplied by
the vendor, the recommended way is to place a symlink to
/dev/null in the configuration directory in
/etc/, with the same filename as the vendor
configuration file.
Configuration is also read from a single configuration file in
/etc/. This file is read before any of the
configuration directories, and has the lowest precedence; entries in a file
in any configuration directory override entries in the single configuration
file.
The following options can be configured in the
"[Sleep]" section of
/etc/systemd/sleep.conf or a
sleep.conf.d file:
SuspendMode=, HibernateMode=, HybridSleepMode=¶The string to be written to
/sys/power/disk by,
respectively,
systemd-suspend.service(8),
systemd-hibernate.service(8), or
systemd-hybrid-sleep.service(8).
More than one value can be specified by separating
multiple values with whitespace. They will be tried
in turn, until one is written without error. If
neither succeeds, the operation will be aborted.
SuspendState=, HibernateState=, HybridSleepState=¶The string to be written to
/sys/power/state by,
respectively,
systemd-suspend.service(8),
systemd-hibernate.service(8), or
systemd-hybrid-sleep.service(8).
More than one value can be specified by separating
multiple values with whitespace. They will be tried
in turn, until one is written without error. If
neither succeeds, the operation will be aborted.
Example: to exploit the “freeze” mode added in Linux 3.9, one can use systemctl suspend with
[Sleep] SuspendState=freeze