Create hibernation.md

hibernation.md

@@ -0,0 +1,134 @@
+# Hibernation
+A few things I've discovered for hibernation, mainly in Ubuntu 20.04/10+(?). 
+
+## Enable hibernation, swap to disk (not partition)
+
+Here is what I did to make it work with Ubuntu 18.04.
+
+-   Make your `/swapfile` have at least the size of your RAM
+
+```
+sudo swapoff /swapfile
+sudo dd if=/dev/zero of=/swapfile bs=$(cat /proc/meminfo | awk '/MemTotal/ {print $2}') count=1024 conv=notrunc
+sudo mkswap /swapfile
+sudo swapon /swapfile
+```
+
+-   Note the UUID of the partition containing your `/swapfile`:
+
+```
+$ sudo findmnt -no UUID -T /swapfile
+20562a02-cfa6-42e0-bb9f-5e936ea763d0
+```
+
+-   Reconfigure the package `uswsusp` in order to correctly use the swapfile:
+
+```
+sudo dpkg-reconfigure -pmedium uswsusp
+# Answer "Yes" to continue without swap space
+# Select "/dev/disk/by-uuid/20562a02-cfa6-42e0-bb9f-5e936ea763d0" replace the UUID with the result from the previous findmnt command
+# Encrypt: "No"
+```
+
+-   Edit the SystemD hibernate service using `sudo systemctl edit systemd-hibernate.service` and fill it with the following content:
+
+```
+[Service]
+ExecStart=
+ExecStartPre=-/bin/run-parts -v -a pre /lib/systemd/system-sleep
+ExecStart=/usr/sbin/s2disk
+ExecStartPost=-/bin/run-parts -v --reverse -a post /lib/systemd/system-sleep
+```
+
+-   Note the resume offset of your `/swapfile`:
+
+```
+$ sudo swap-offset /swapfile
+resume offset = 34818
+```
+
+-   Configure Grub to resume from the swapfile by editing `/etc/default/grub` and modify the following line:
+
+```
+GRUB_CMDLINE_LINUX_DEFAULT="resume=UUID=20562a02-cfa6-42e0-bb9f-5e936ea763d0 resume_offset=34818 quiet splash"
+```
+
+-   Update Grub:
+
+```
+sudo update-grub
+```
+
+-   Create the following `/etc/initramfs-tools/conf.d/resume`:
+
+```
+RESUME=UUID=20562a02-cfa6-42e0-bb9e-5e936ea763d0 resume_offset=34816
+    # Resume from /swapfile
+
+```
+
+-   Update initramfs:
+
+```
+sudo update-initramfs -u -k all
+```
+
+Now you can hibernate with `sudo systemctl hibernate`.
+
+One can also create those scripts:
+
+```
+sudo tee /usr/local/bin/gotosleep <<EOF
+dbus-send --type=method_call --dest=org.gnome.ScreenSaver /org/gnome/ScreenSaver org.gnome.ScreenSaver.Lock
+sleep 2
+sudo /usr/sbin/s2both
+EOF
+sudo chmod +x /usr/local/bin/gotosleep
+sudo tee /usr/local/bin/gotohibernation <<EOF
+dbus-send --type=method_call --dest=org.gnome.ScreenSaver /org/gnome/ScreenSaver org.gnome.ScreenSaver.Lock
+sleep 2
+sudo systemctl hibernate
+EOF
+sudo chmod +x /usr/local/bin/gotohibernation
+```
+
+So you can sleep with `gotosleep` or hibernate with `gotohibernation`.
+
+You must be able to execute `sudo s2both`, `sudo s2ram` and `sudo systemctl hibernate`without having to enter your password for the previous scripts to work.
+
+You could do that for example by creating a `powerdev` group, add your current user to it, and configure the following sudoers config (edit it with `sudo visudo -f /etc/sudoers.d/powerdev`):
+
+```
+%powerdev ALL=NOPASSWD: /usr/sbin/s2both, /usr/sbin/s2ram, /bin/systemctl hibernate
+
+```
+
+Documentation used:
+
+-   [Cas' answer](https://askubuntu.com/a/892410/29219)
+-   [Debian "Hibernate without swap partition"](https://wiki.debian.org/Hibernation/Hibernate_Without_Swap_Partition)
+-   [Configuring Lubuntu 18.04 to enable hibernation using a swap file](https://fitzcarraldoblog.wordpress.com/2018/07/14/configuring-lubuntu-18-04-to-enable-hibernation-using-a-swap-file/)
+-   [So question "s2disk works, but hibernation from menu gets stuck afer login"](https://askubuntu.com/q/1035345/29219)
+
+## Enable suspend then hibernate 
+This enables ubuntu/linux to suspend then after a set amount of time hibernaate
+
+To start using this function (suspend-then-hibernate) you need to create a file ```/etc/systemd/sleep.conf``` with the next content:
+
+```
+[Sleep]
+HibernateDelaySec=3600
+```
+Then you can test it by command:
+
+```sudo systemctl suspend-then-hibernate```
+
+you can edit ```HibernateDelaySec``` to reduce delay to hibernate.
+
+If all works fine you can change Lid Close Action, to do it you need to edit the file ```/etc/systemd/logind.conf```
+
+You need to find option ```HandleLidSwitch=```, uncomment it and change to ```HandleLidSwitch=suspend-then-hibernate```. Then you need to restart systemd-logind service (warning! you user session will be restarted) by the next command:
+
+```sudo systemctl restart systemd-logind.service```
+
+That's all! Now you can use this nice function. (via [StackOverflow](https://askubuntu.com/questions/12383/how-to-go-automatically-from-suspend-into-hibernate))