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.

           Added in version 203.

       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.

           Added in version 203.

       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.

           Added in version 203.

       suspend-then-hibernate
           A low power state where the system is initially suspended (the state is stored in RAM). When the
           battery level is too low (less than 5%) or a certain timespan has passed, whichever happens first,
           the system is automatically woken up and then hibernated. This establishes a balance between speed
           and safety.

           If the system has no battery, it would be hibernated after HibernateDelaySec= has passed. If not set,
           then defaults to "2h".

           If the system has battery and HibernateDelaySec= is not set, low-battery alarms (ACPI _BTP) are tried
           first for detecting battery percentage and wake up the system for hibernation. If not available, or
           HibernateDelaySec= is set, the system would regularly wake up to check the time and detect the
           battery percentage/discharging rate. The rate is used to schedule the next detection. If that is also
           not available, SuspendEstimationSec= is used as last resort.

           Added in version 239.

       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. The main configuration file is either in /usr/lib/systemd/ or
       /etc/systemd/ and contains commented out entries showing the defaults as a guide to the administrator.
       Local overrides can be created by creating drop-ins, as described below. The main configuration file can
       also be edited for this purpose (or a copy in /etc/ if it's shipped in /usr/) however 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. This also
       defined a concept of drop-in priority to allow distributions to ship drop-ins within a specific range
       lower than the range used by users. This should lower the risk of package drop-ins overriding
       accidentally drop-ins defined by users.

       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=, AllowHybridSleep=, AllowSuspendThenHibernate=
           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.

           Added in version 240.

       HibernateMode=
           The string to be written to /sys/power/disk by systemd-hibernate.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 page Basic sysfs Interfaces for System
           Suspend and Hibernation[1] for more details.

           systemd-suspend-then-hibernate.service(8) uses the value of HibernateMode= when hibernating.

           Added in version 203.

       SuspendState=
           The string to be written to /sys/power/state by systemd-suspend.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 Basic sysfs Interfaces for System Suspend and Hibernation[1] for
           more details.

           systemd-suspend-then-hibernate.service(8) uses this value when suspending.

           Added in version 203.

       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). Refer to
           suspend-then-hibernate for details on how this option interacts with other options/system battery
           state.

           Added in version 239.

       SuspendEstimationSec=
           The RTC alarm will wake the system after the specified timespan to measure the system battery
           capacity level and estimate battery discharging rate. Only used by systemd-suspend-then-
           hibernate.service(8). Refer to suspend-then-hibernate for details on how this option interacts with
           other options/system battery state.

           Added in version 253.

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. Basic sysfs Interfaces for System Suspend and Hibernation
           https://www.kernel.org/doc/html/latest/admin-guide/pm/sleep-states.html#basic-sysfs-interfaces-for-system-suspend-and-hibernation