Suspend and hibernate

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This article describes how to suspend or hibernate a Gentoo system.



Make sure support for suspend and hibernation has been activated (CONFIG_SUSPEND) and (CONFIG_HIBERNATION):

Power management and ACPI options --->
    [*] Suspend to RAM and standby
    [*] Hibernation (aka 'suspend to disk')


The following software can be used for in-kernel default suspend/hibernate implementation, namely, swsusp.

root #emerge --ask sys-power/suspend

Another alternative is sys-power/hibernate-script which can be used with swsusp.

Optional: Install upower and consolekit

Some desktop environments might require sys-power/upower and ConsoleKit with USE="pm-utils" [1] for showing "Suspend" and "Hibernate" buttons in their menu. In case sys-power/upower-pm-utils was installed it must be unmerged.

root #emerge --unmerge sys-power/upower-pm-utils
root #emerge --ask sys-power/upower
root #echo "sys-auth/consolekit pm-utils" >> /etc/portage/package.use
root #emerge --ask --oneshot sys-auth/consolekit

Available suspend modes

To see available suspend modes use

root #cat /sys/power/state

for swsusp, default implementation.

Those two file will list at least ACPI S2/4 power down methods on modern hardware. New hardware would also support S5 method which is a rough S4 method. ACPI S2 correspond to suspend to ram (ram method in swsusp terms and 3 in ToI terms); S4 hibernation to disk (disk in swsusp temrs and 4 in ToI terms; S5 hibernation to disk (5 in ToI terms).

Swsusp users can choose between platfom, meaning ACPI, or *shutdown* methods which can be echo-ed to `/sys/power/disk' sysfs file.

Suspend to RAM

Preferred commands to suspend are:

root #pm-suspend


root #s2ram


root #hibernate-ram

For suspend (to ram) for hibernate-script users; or

root #hibernate

to hibernate (to disk.)

A more raw method is to

root #echo mem > /sys/power/state

Suspend to disk


If you are using genkernel initramfs, you may experience bug #156445 which makes it impossible to resume after suspend-to-disk. There is a number of ways to avoid it, from editing initramfs (e.g. as described here) to dropping genkernel completely. sys-kernel/genkernel-next works just fine.

For suspend to disk to operate a swap partition or swap file must exist.

The swap file should be active beforehand and should be echoed on the appropriate file before any attempt to suspend/hibernate.

root #echo /dev/sda1 > /sys/power/resume

A more raw method is to:

root #echo disk > /sys/power/state

Do not forget to probe:

root #cat /sys/power/tuxonice/swap/headerlocations

before issuing an actual command and append the result to kernel command line argument prepended with `resume='. This will suffice to resume from a block device or swap file for ToI. However, it's more complicated for a swapfile with swsusp.

Suspend to disk with sys-power/pm-utils

Yet another way to achieve disk hibernation is to use hibernate to swap partition and pm-utils.

First, make sure a swap partition has been set:

root #swapon -s

For this example, we will assume it's /dev/sdc2

Edit /etc/default/grub and append the resume kernel option to GRUB_CMDLINE_LINUX_DEFAULT pointing to the swap partition.

FILE /etc/default/grubGRUB Config

Rebuild the GRUB config:

root #grub-mkconfig -o /boot/grub/grub.cfg

Update initramfs:

root #genkernel --install initramfs

Add the following to /etc/pm/config.d/gentoo (see bug 338239):

FILE /etc/pm/config.d/gentoo

Reboot the system:

root #reboot

Next, try

root #pm-hibernate

Suspend to disk with swapfile

You can use suspend to disk with a swapfile. When you have a functional swapfile you need to configure kernel parameters (via GRUB, etc.).

First find UUID of device where your swapfile resides. For example: /dev/sda1.

If swapfile resides in a LVM volume, GRUB must be compiled with LVM support. Otherwise, the system will not wake up and will be cold started.
root #blkid /dev/sda1

Find offset of swapfile on given partition using swap-offset utility from sys-power/suspend:

root #swap-offset /path/to/swapfile

After that edit GRUB config and add required parameters to boot string:

FILE /etc/defaults/grubGRUB defaults
GRUB_CMDLINE_LINUX_DEFAULT="resume=UUID=<UUID_of_partition> resume_offset=<offset_of_swapfile>"

Rebuild GRUB config:

root #grub-mkconfig -o /boot/grub/grub.cfg

Reboot the system and check used kernel parameters:

user $cat /proc/cmdline

It should now be possible to hibernate the system.

Remember, swap file must contain all memory used by running processes and memory based filesystems like tmpfs or zram prior to hibernating. However, unless specifically set, the hibernation image is compressed. Setting hibernation image size to half of the amount of installed RAM is a safe value in most cases. One of the cases where this does not fully apply is when the system has a high usage of zswap which means that memory may already be compressed.


If troubleshooting suspend the powersave log might be useful:

root #less /var/log/pm-powersave.log

Also classic kernel buffer comes handy:

user $dmesg

Can not resume after suspend

In case resuming from suspend does not work, disable the security chip setting in BIOS/UEFI and try again.

Make sure you change the /etc/pm/config.d/gentoo file as described above.

See also

External resources