If you have upgraded to Ubuntu 12.04, one thing that you will find missing is the “Hibernate” button. For those of you who are not aware or don’t use this feature at all, the Hibernate button usually lies above the Shut Down option and it allows you to save your current state to the hard drive so the next time you boot up, it can restore to the previous saved state without going through the usual boot up loop.
Why Hibernate is disabled by default in Ubuntu 12.04?
Some of you who are used to the Hibernate feature in Ubuntu might be asking “why is this missing in Ubuntu 12.04?”
The reason behind this is because Ubuntu’s Hibernate feature has always not been working well in many computers. For new hardware models, the Hibernate feature often don’t work by default. In some instances, the Hibernate feature will even lead to data loss. The rationale behind the removal of the Hibernate button is:
For Ubuntu to present a Suspend function that doesn’t work is unprofessional, and presenting a Hibernate function that doesn’t work (and destroys data by never waking up) is even worse.
After much discussion and debating, the final decision is to disable Hibernate by default on all computers, unless the computer is on a whitelist. The whitelist will include all “Ubuntu Certified” computers that have been tested and proven to work with the Hibernate feature. So if you are not seeing the Hibernate button, most probably your PC is not “Ubuntu Certified”.
Where to access the Hibernate feature?
Currently, the Hibernate feature is only available in the “Power -> When power is critically low” settings. You can get your laptop to go into Hibernate mode when your batter power is critically low.
How to get back the Hibernate feature?
If you are not sure if your PC supports the Hibernate feature, open a terminal and type
pm-hibernate. If your PC succeed in going to Hibernate mode and you have no problem waking it up, your PC supports the Hibernate feature. You can then proceed to the next step to restore the Hibernate option.
In the terminal and open the following file:
sudo nano /etc/polkit-1/localauthority/50-local.d/com.ubuntu.desktop.pkla
Add the following:
[Re-enable hibernate by default] Identity=unix-user:* Action=org.freedesktop.upower.hibernate ResultActive=yes
Save (Ctrl + o) and exit (Ctrl + x).
Restart the PC. The Hibernate option should return now.