Search notes:

/sys/power

The power management subsystem provides userspace with a unified sysfs interface for system sleep located in the /sys/power directory.

Files found under /sys/power include

`disk`	What the kernel does after creating a hibernation image.
`image_size`	controls the size of hibernation images. writing '0' to this file will enforce hibernation images to be as small as possible.
`mem_sleep`
`pm_async`
`pm_debug_messages`
`pm_freeze_timeout`
`pm_print_times`
`pm_test`
`pm_trace`
`pm_trace_dev_match`
`pm_wakeup_irq`
`reserved_size`
`resume`
`resume_offset`
`state`	the system sleep state control file: it contains a line of supported sleep states (`freeze`, `standby`, `mem`, `disk`), separated by a whitespace. (See also Documentation/admin-guide/pm/sleep-states.rst)
`sysn_on_suspend`
`wakeup_count`

There is also a suspend_stats subdirectory.

See also