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

Provided by: systemd_256.5-2ubuntu4_amd64

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's 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.

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

NAME

SYNOPSIS

DESCRIPTION

CONFIGURATION DIRECTORIES AND PRECEDENCE

OPTIONS

EXAMPLE: FREEZE

SEE ALSO

NOTES