Power saving for laptops

sudo apt-get install powertop indicator-power upower laptop-mode-tools

then run the following

gksu lmt-config-gui ;for laptop mode tools
sudo powertop --calibrate ;note will run for some time

turn off bluetooth, check power settings for suspends

1). Enter the following in terminal: sudo gedit /etc/rc.local

2). Enter: rfkill block bluetooth

Suspend and hibernate

Suspend saves everthing to RAM, hibernate to disk. Suspend wakes up faster, Hibernate saves your batteries more. Hybrid modes try to combine the best of both worlds.

Ubuntu guide how to hibernate my computer and test it

Hibertnate will not wake up properly with an encrypted swap partition by default. This is how to go about getting it to work

Archlinux page on suspend and hibernate

good Archlinux thread on troubleshooting

A great article on various types of suspend and hibernate, how to check if your machine works with the kernel or requires different types of suspend / hibernates

Hibernate

ways to hibernate

pm-hibernate

is a collection of scripts that solve a lot of strange hibernation problems and bugs (see the man page). They should not be needed any more

systemctl hibernate

is the way you should be hibernating [1]

[2]

[3]

needs trying

systemd-sleep

apparently a disaster.

Uswsusp

A collection of suspend tools:

s2ram, s2disk, s2both

[4]

[5] (didn't work for me) NB not tried this yet.

How to Enable Hibernate in Ubuntu Linux

swapping

You can create a swap file or use a swap partition. It makes a difference if the file / partition is encrypted or not. It makes a difference if your swap is encrypted or not. a good general article on creating files or partitions NB. apparently for some people the solution is to create a swap file (haven't tried this yet)

swapon -s

will tell you if your swap is running or not.

swap files

[6]

[7]

[8]

find out if your swap partition is encrypted

  blkid | grep swap

Turn encryption on

That is pretty simple

  sudo ecryptfs-setup-swap

Turn swapfile enctyption off

The idea is to turn off swap, remove the ecryptfs layer, reformat your partition with normal swap and enable it. We use sda5 as an example for the swap partition, please use your own (fdisk -l will tell you which swap partition you are using - or in /etc/crypttab)

sudo swapoff -a
sudo cryptsetup remove /dev/mapper/cryptswap1
sudo vim /etc/crypttab
*remove the /dev/sda5 line*
sudo /sbin/mkswap /dev/sda5
sudo swapon /dev/sda5
sudo vim /etc/fstab
*replace /dev/mapper/cryptswap1 with /dev/sda5*

how to disable encryption on your swap file

edits to enable hibernation

Edit this file: /var/lib/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla

eg.: sudo gedit /var/lib/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla

Add this content:

[Re-enable hibernate by default in upower]
Identity=unix-user:*
Action=org.freedesktop.upower.hibernate
ResultActive=yes

[Re-enable hibernate by default in logind]
Identity=unix-user:*
Action=org.freedesktop.login1.hibernate
ResultActive=yes

This will add hibernate option in menu. But if you want to hibernate, when LID will close, then execute this (this will enable hibernation when LID is closed):

sudo sed -i 's/#HandleLidSwitch=suspend/HandleLidSwitch=hibernate/g' /etc/systemd/logind.conf

And restart system or execute: sudo systemctl restart systemd-logind.service (https://unix.stackexchange.com/questions/125832/no-hibernate-option-in-power-manager-on-mint-16-mate)

---

If you have change your hard disk or the partition table, then your computer will save a session, but it won't be able to resume it upon power up, acting as if it was rebooted rather than hibernated.

In this case, you have to inform initramfs-tools about the correct partition uuid. First of all, take note of the id of your swap partition with

$ ls /dev/disk/by-uuid -la

Then, edit the file /etc/initramfs-tools/conf.d/resume accordingly.

Finally update initramfs with

# update-initramfs -u

It it still doesn't work, try to specify the restore partition to Grub too. However, it should not be necessary.

Edit the file /etc/default/grub specifying the UUID of your swap partition:

GRUB_CMDLINE_LINUX="resume=UUID=6098d082-4654-4840-8937-7337d14b2c5d other-option=value"

or simply use the device

GRUB_CMDLINE_LINUX="resume=/dev/sda1 other-option=value"

Don't forget to update Grub.

# update-grub

Reboot, and try to hibernate:

# pm-hibernate

https://unix.stackexchange.com/questions/8827/hibernate-to-disk-not-restoring-but-suspend-to-ram-is-working

Other files

/sys/power/resume

/sys/power/resume_offset

/sys/power/reserverd_size