SYSTEMD-HIBERNATE-RESUME.SERVICE(8) systemd-hibernate-resume.service SYSTEMD-HIBERNATE-RESUME.SERVICE(8)

systemd-hibernate-resume.service, systemd-hibernate-resume - Resume from hibernation

systemd-hibernate-resume.service

/usr/lib/systemd/systemd-hibernate-resume

systemd-hibernate-resume.service initiates the resume from hibernation.

systemd-hibernate-resume only supports the in-kernel hibernation implementation, see Swap suspend[1]. Internally, it works by writing the major:minor of specified device node to /sys/power/resume, along with the offset in memory pages (/sys/power/resume_offset) if supported.

Failing to initiate a resume is not an error condition. It may mean that there was no resume image (e. g. if the system has been simply powered off and not hibernated). In such cases, the boot is ordinarily continued.

systemd(1), systemd-hibernate-resume-generator(8)

1.
Swap suspend
https://docs.kernel.org/power/swsusp.html
systemd 255