• poma's avatar
    Hybrid Sleep support - "hibernate" and suspend the system · 37f681e6
    poma authored
    Hybrid Sleep initially only writes hibernation image to SWAP space,
    it does not power off the machine, as a whole Suspend To Disk (S4) does,
    it rather Suspend To RAM (S3).
    
    The benefit of this combination is pronto RESUME from S3,
    whilst in case of battery drained or interruptions in power supply of any kind,
    you ain't gonna lose your work.
    
    Hybrid Sleep is the feature of the Linux kernel.
    To test it directly via cli:
    echo suspend > /sys/power/disk ; echo disk > /sys/power/state
    
    However to make this feature work,
    both Suspend To RAM (S3) and Suspend To Disk (S4)
    must be provided by the hardware
    dmesg:
    ACPI: (supports ... S3 S4 ...)
    in working order.
    
    Furthermore Suspend To Disk (S4) requires a relatively simple configuration
    an appendix to kernel command line:
    resume=<path to resume partition>
    i.e. directive to utilize particular SWAP space
    man 7 dracut.cmdline
    
    Ref.
    https://www.kernel.org/doc/Documentation/power/swsusp.txtSigned-off-by: default avatarEric Koegel <eric.koegel@gmail.com>
    37f681e6