SYSTEMD-SLEEP.CONF(5) systemd-sleep.conf SYSTEMD-SLEEP.CONF(5)
NAME
systemd-sleep.conf, sleep.conf.d - Suspend and hibernation
configuration file
SYNOPSIS
/etc/systemd/sleep.conf
/etc/systemd/sleep.conf.d/*.conf
/run/systemd/sleep.conf.d/*.conf
/usr/lib/systemd/sleep.conf.d/*.conf
DESCRIPTION
systemd supports four general power-saving modes:
suspend
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.
hibernate
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.
hybrid-sleep
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.
suspend-then-hibernate
A low power state where the system is initially suspended (the
state is stored in RAM). If the system supports low-battery alarms
(ACPI _BTP), then the system will be woken up by the ACPI
low-battery signal and hibernated (the state is then stored on
disk). Also, if not interrupted within the timespan specified by
HibernateDelaySec= or the estimated timespan until the system
battery charge level goes down to 5%, then the system will be woken
up by the RTC alarm and hibernated. The estimated timespan is
calculated from the change of the battery capacity level after the
time specified by SuspendEstimationSec= or when the system is woken
up from the suspend.
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. See
systemd.syntax(7) for a general description of the syntax.
CONFIGURATION DIRECTORIES AND PRECEDENCE
The default configuration is set during compilation, so configuration
is only needed when it is necessary to deviate from those defaults.
Initially, the main configuration file in /etc/systemd/ contains
commented out entries showing the defaults as a guide to the
administrator. Local overrides can be created by editing this file or
by creating drop-ins, as described below. Using drop-ins for local
configuration is recommended over modifications to the main
configuration file.
In addition to the "main" configuration file, drop-in configuration
snippets are read from /usr/lib/systemd/*.conf.d/,
/usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/. Those
drop-ins have higher precedence and override the main configuration
file. Files in the *.conf.d/ configuration subdirectories are sorted by
their filename in lexicographic order, regardless of in which of the
subdirectories they reside. When multiple files specify the same
option, for options which accept just a single value, the entry in the
file sorted last takes precedence, and for options which accept a list
of values, entries are collected as they occur in the sorted files.
When packages need to customize the configuration, they can install
drop-ins under /usr/. Files in /etc/ are reserved for the local
administrator, who may use this logic to override the configuration
files installed by vendor packages. Drop-ins have to be used to
override package drop-ins, since the main configuration file has lower
precedence. It is recommended to prefix all filenames in those
subdirectories with a two-digit number and a dash, to simplify the
ordering of the files.
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.
OPTIONS
The following options can be configured in the [Sleep] section of
/etc/systemd/sleep.conf or a sleep.conf.d file:
AllowSuspend=, AllowHibernation=, AllowSuspendThenHibernate=,
AllowHybridSleep=
By default any power-saving mode is advertised if possible (i.e.
the kernel supports that mode, the necessary resources are
available). Those switches can be used to disable specific modes.
If AllowHibernation=no or AllowSuspend=no is used, this implies
AllowSuspendThenHibernate=no and AllowHybridSleep=no, since those
methods use both suspend and hibernation internally.
AllowSuspendThenHibernate=yes and AllowHybridSleep=yes can be used
to override and enable those specific modes.
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 none of
the writes succeed, the operation will be aborted.
The allowed set of values is determined by the kernel and is shown
in the file itself (use cat /sys/power/disk to display). See the
kernel documentation[1] for more details.
systemd-suspend-then-hibernate.service(8) uses the value of
SuspendMode= when suspending and the value of HibernateMode= when
hibernating.
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 none of
the writes succeed, the operation will be aborted.
The allowed set of values is determined by the kernel and is shown
in the file itself (use cat /sys/power/state to display). See the
kernel documentation[1] for more details.
systemd-suspend-then-hibernate.service(8) uses the value of
SuspendState= when suspending and the value of HibernateState= when
hibernating.
HibernateDelaySec=
The amount of time the system spends in suspend mode before the
system is automatically put into hibernate mode. Only used by
systemd-suspend-then-hibernate.service(8). If the system has a
battery, then defaults to the estimated timespan until the system
battery charge level goes down to 5%. If the system has no battery,
then defaults to 2h.
SuspendEstimationSec=
The RTC alarm will wake the system after the specified timespan to
measure the system battery capacity level and estimate battery
discharging rate, which is used for estimating timespan until the
system battery charge level goes down to 5%. Only used by systemd-
suspend-then-hibernate.service(8). Defaults to 1h.
EXAMPLE: FREEZE
Example: to exploit the “freeze” mode added in Linux 3.9, one can use
systemctl suspend with
[Sleep]
SuspendState=freeze
SEE ALSO
systemd-sleep(8), systemd-suspend.service(8), systemd-
hibernate.service(8), systemd-hybrid-sleep.service(8), systemd-suspend-
then-hibernate.service(8), systemd(1), systemd.directives(7)
NOTES
1. the kernel documentation
https://www.kernel.org/doc/html/latest/admin-guide/pm/sleep-states.html#basic-sysfs-interfaces-for-system-suspend-and-hibernation
systemd 252 SYSTEMD-SLEEP.CONF(5)
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