Hibernation

Hibernation (also known as suspend-to-disk) is a method used to power down a computer while preserving the state of the operating system. Once powered up, the operating system will be in the exact state as it was at the time of hibernation.

In Slackware, hibernation works out-of-the-box. However, in order to resume successfully from a hibernated state, you need to configure the bootloader so it knows where to locate the resume data.

KDE, XFCE and other desktop environments offer hibernation from logout screen/menu.

You can hibernate your system from console. Either as root via pm-utils or D-Bus with additional programs as regular user.

Hibernation is done via pm-hibernate command.

Slackware offers two services to control power management in it's recent releases. UPower and HAL. Since HAL is deprecated in favor of UPower, use HAL in older Slackware releases (from 12.0 to 13.37), otherwise use UPower.

Use one of these command to hibernate your system.

 $ dbus-send --system --print-reply --dest="org.freedesktop.UPower" \
 /org/freedesktop/UPower org.freedesktop.UPower.Hibernate

$ dbus-send --system --print-reply --dest="org.freedesktop.Hal" \
 /org/freedesktop/Hal/devices/computer org.freedesktop.Hal.Device.SystemPowerManagement.Hibernate

To tell your kernel where to resume from, you need to write the info to lilo.conf:

append=" resume=/dev/sdaX"

Replace /dev/sdaX with your actual swap space. Swap partitions are perfect, I think swap files should work too.

LILO doesn't support booting from LVM, therefore you have to create initial ramdisk (initrd). You need one even though your kernel has build-in support for LVM.

You don't have to specially adjust lilo.conf because you can set everything resume-related in initrd.

mkinitrd -c -k <kernel-version> -f <fs_type> -m <modules_required_to_boot> -r <root_partition> -h /dev/volumegroup/swap -L

• -h set your hibernation/swap logical volume
• -L activate LVM

Next step is to make sure your lilo.conf contains following snippet

image = /boot/vmlinuz
  root = /dev/sdaX
  initrd = /boot/initrd.gz
  label = Slackware
  read-only # Partitions should be mounted read-only

Afterwards, run lilo to save changes.

$ lilo

• Hibernate to encrypted swap - http://slackware.osuosl.org/slackware-13.1/README_CRYPT.TXT REAME_CRYPT.TXT

• Original source: http://www.slackwiki.com/Hibernate
  • Original author unknown - original submissions 1,2
  • Otherwise rewritten by me (Martin Matějek) also on Slackwiki