# systemd-sleep.conf

## NAME



           systemd-sleep.conf, sleep.conf.d - Suspend and hibernation
           configuration file
    


## SYNOPSIS



               /etc/systemd/sleep.conf
               /run/systemd/sleep.conf
               /usr/lib/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 loaded from one of
           the listed directories in order of priority, only the first file
           found is used: /etc/systemd/, /run/systemd/,
           /usr/local/lib/systemd/ [1], /usr/lib/systemd/. The vendor version
           of the file contains commented out entries showing the defaults as
           a guide to the administrator. Local overrides can also 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
           is shipped under /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. This also defines a concept of
           drop-in priorities to allow OS vendors 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. It is recommended to use the range
           10-40 for drop-ins in /usr/ and the range 60-90 for drop-ins in
           /etc/ and /run/, to make sure that local and transient drop-ins
           take priority over drop-ins shipped by the OS vendor.
    
           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.
    
           _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******[2] for more details.systemd-suspend-then-hibernate.service(8) uses this value when
               suspending.
    
               Added in version 203.
    
           _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******[2] for more details.systemd-suspend-then-hibernate.service(8) uses the value of
               _HibernateMode=_ when hibernating.
    
               Added in version 203.
    
           _MemorySleepMode=_
               The string to be written to /sys/power/mem_sleep when
               **SuspendState=mem** or **hybrid-sleep** is used. 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. Defaults to empty, i.e. the kernel default or
               kernel command line option _mem_sleep_default=_ is respected.
    
               The allowed set of values is determined by the kernel and is
               shown in the file itself (use **cat /sys/power/mem_sleep** to
               display). See the kernel documentation page **Basic sysfs**
               **Interfaces for System Suspend and Hibernation******[2] for more
               details.
    
               Added in version 256._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.
    
           _HibernateOnACPower=_
               Whether to allow hibernation when the system has AC power.
               Only used by systemd-suspend-then-hibernate.service(8) when
               _HibernateDelaySec=_ is set.
    
               If this option is disabled, the countdown of
               _HibernateDelaySec=_ starts only after AC power is disconnected,
               keeping the system in the suspend state otherwise.
    
               This option is only effective on systems with a battery.
    
               Added in version 257.
    
           _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
    


## NOTES



            1. 💣💥🧨💥💥💣 Please note that those configuration files must
               be available at all times. If /usr/local/ is a separate
               partition, it may not be available during early boot, and must
               not be used for configuration.
    
            2. Basic sysfs Interfaces for System Suspend and Hibernation
               https://docs.kernel.org/admin-guide/pm/sleep-states.html#basic-sysfs-interfaces-for-system-suspend-and-hibernation
    


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