systemd systemd-sleep.conf 5 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 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-sleep8 when systemd1 attempts to suspend or hibernate the machine. See systemd.syntax7 for a general description of the syntax. 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. HibernateMode= The string to be written to /sys/power/disk by systemd-hibernate.service8. 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 for more details. systemd-suspend-then-hibernate.service8 uses the value of HibernateMode= when hibernating. SuspendState= The string to be written to /sys/power/state by systemd-suspend.service8. 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 for more details. systemd-suspend-then-hibernate.service8 uses this value when suspending. 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.service8. 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.service8. Defaults to 1h. Example: to exploit the freeze mode added in Linux 3.9, one can use systemctl suspend with [Sleep] SuspendState=freeze systemd-sleep8 systemd-suspend.service8 systemd-hibernate.service8 systemd-hybrid-sleep.service8 systemd-suspend-then-hibernate.service8 systemd1 systemd.directives7