This page presents hibernation under Debian.

Uswsusp

uswsusp is the default hibernation tool in ["DebianEtch"]. It uses an existing swap partition to saved the memory state (see /etc/uswsusp.conf).

hibernate

ToDo : write this paragraph.

Debugging hibernation

Kernel testing facility

Since linux 2.6.25, the kernel has a new Hibernation testing facility [http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=4cc79776c9ea431790e04fcacbebb30d28eb1570 changelog].

Make it possible to test the hibernation core code with the help of the /sys/power/pm_test attribute introduced for suspend testing in the previous patch.

Writing an appropriate string to this file causes the hibernation code to work in one of the test modes defined as follows:

freezer
test the freezing of processes
devices
test the freezing of processes and suspending of devices
platform
test the freezing of processes, suspending of devices and platform global control methods(*)
processors
test the freezing of processes, suspending of devices, platform global control methods(*) and the disabling of nonboot CPUs
core
test the freezing of processes, suspending of devices, platform global control methods(*), the disabling of nonboot CPUs and suspending of platform/system devices

*) The platform global control methods are only available on ACPI systems and are only tested if the hibernation mode is set to "platform"

Then, if a hibernation is started by normal means, the hibernation core will perform its normal operations up to the point indicated by given test level. Next, it will wait for 5 seconds and carry out the resume operations needed to transition the system back to the fully functional state.

The actual message (for googlers) are hibernation debug: Waiting for 5 seconds and swsusp debug: Waiting for 5 seconds.