Table of Contents

1. Hibernation on Debian without swap partition
   1. Enabling hibernation on Debian (bookworm-testing-trixie)
      1. Create swapfile and configure it
      2. Update grub and initramfs
      3. Test hibernation straight away
   2. Enabling suspend-then-hibernate
      1. Create the file /etc/systemd/system/suspend-sedation.service
      2. Enable it with
   3. Customizing suspend-then-hibernate
      1. Tests for preparing version with hibernating only if battery is low and laptop is not on ac power

TODO Hibernation on Debian without swap partition

Enabling hibernation on Debian (bookworm-testing-trixie)

I followed the instruction found here: https://wiki.debian.org/Hibernation/Hibernate_Without_Swap_Partition

Create swapfile and configure it

fallocate -l 64GiB /media/mb/arch/swapfile

mkswap /media/mb/arch/swapfile
chmod 600 /media/mb/arch/swapfile

sudo chmod 600 /media/mb/arch/swapfile

Then I added:

/media/mb/arch/swapfile   swap    swap    defaults        0       0 

to my /etc/fstab.

Then I stopped the kernel from using the swap file for swapping:

sudo sysctl -w vm.swappiness=1 

Activated the swap file:

sudo swapon /media/mb/arch/swapfile

Update grub and initramfs

1. get UUID of the partition storing swapfile

   findmnt /media/mb/arch -o UUID -n
   

2. … and offset of the file

   sudo filefrag -v /media/mb/arch/swapfile|awk 'NR==4{gsub(/\./,"");print $4;}'
   

3. now put those in /etc/default/grub

   GRUB_CMDLINE_LINUX_DEFAULT="resume=UUID=xxxx resume_offset=yyyyy"
   

   which in my case was:

   GRUB_CMDLINE_LINUX_DEFAULT="resume=UUID=b3dd82eb-4174-4ba5-a557-8972bafc04ba resume_offset=135047168"
   

4. put UUID in /etc/initramfs-tools/conf.d/resume

   Append line

   RESUME=UUID=b3dd82eb-4174-4ba5-a557-8972bafc04ba
   

5. regenerate both grub config and initramfs

   sudo update-grub
   sudo update-initramfs -k all -u
   

Test hibernation straight away

systemctl hibernate

… it’s working!

Enabling suspend-then-hibernate

I followed the instructions here: https://wiki.debian.org/SystemdSuspendSedation

Create the file /etc/systemd/system/suspend-sedation.service

with the following content (I did extended the suspend-time from 5 minutes (300) to 30 minutes (1800 in line Environment="ALARM_SEC=1800"):

3600 = 1h 7200 = 2h

# ## MB note: 
# ## file created in order to enable suspend-then-hibernate
# ## according to https://wiki.debian.org/SystemdSuspendSedation

# /etc/systemd/system/suspend-sedation.service
[Unit]
Description=Hibernate after suspend
Documentation=https://bbs.archlinux.org/viewtopic.php?pid=1420279#p1420279
Documentation=https://bbs.archlinux.org/viewtopic.php?pid=1574125#p1574125
Documentation=https://wiki.archlinux.org/index.php/Power_management
Documentation=http://forums.debian.net/viewtopic.php?f=5&t=129088
Documentation=https://wiki.debian.org/SystemdSuspendSedation
Conflicts=hibernate.target hybrid-sleep.target
Before=sleep.target
StopWhenUnneeded=true

[Service]
Type=oneshot
RemainAfterExit=yes
# 1800"
Environment="ALARM_SEC=1800" 
Environment="WAKEALARM=/sys/class/rtc/rtc0/wakealarm"

ExecStart=/usr/sbin/rtcwake --seconds $ALARM_SEC --auto --mode no
ExecStop=/bin/sh -c '\
ALARM=$(cat $WAKEALARM); \
NOW=$(date +%%s); \
if [ -z "$ALARM" ] || [ "$NOW" -ge "$ALARM" ]; then \

  if [ $(cat /sys/class/power_supply/AC/online) == '0' ]; then
    echo 'On battery'

    if [ $(cat /sys/class/power_supply/BAT0/capacity) -lt 50 ]; then      
      echo 'Battery less than 50%'
      # perform hibernation
      echo "suspend-sedation: Woke up - no alarm set. Hibernating..."; \
      systemctl hibernate; \
    else
      # put it to sleep once again
      systemctl suspend; \      
    fi

  else
    echo 'On AC power'
    systemctl suspend; \
  fi   

else \
  echo "suspend-sedation: Woke up before alarm - normal wakeup."; \
  /usr/sbin/rtcwake --auto --mode disable; \
fi \
'

[Install]
WantedBy=sleep.target

1. New version that performs hibernation from suspension only if laptop is not on battery and has less than 50% of battery

   Basing on this: https://askubuntu.com/questions/75886/how-do-i-set-the-computer-to-suspend-when-battery-is-critically-low

   # ## MB note: 
   # ## file created in order to enable suspend-then-hibernate
   # ## according to https://wiki.debian.org/SystemdSuspendSedation
       
   # /etc/systemd/system/suspend-sedation.service
   [Unit]
   Description=Hibernate after suspend
   Documentation=https://bbs.archlinux.org/viewtopic.php?pid=1420279#p1420279
   Documentation=https://bbs.archlinux.org/viewtopic.php?pid=1574125#p1574125
   Documentation=https://wiki.archlinux.org/index.php/Power_management
   Documentation=http://forums.debian.net/viewtopic.php?f=5&t=129088
   Documentation=https://wiki.debian.org/SystemdSuspendSedation
   Conflicts=hibernate.target hybrid-sleep.target
   Before=sleep.target
   StopWhenUnneeded=true
       
   [Service]
   Type=oneshot
   RemainAfterExit=yes
   # 1800"
   Environment="ALARM_SEC=1800" 
   Environment="WAKEALARM=/sys/class/rtc/rtc0/wakealarm"
       
   ExecStart=/usr/sbin/rtcwake --seconds $ALARM_SEC --auto --mode no
   ExecStop=/bin/sh -c '\
   ALARM=$(cat $WAKEALARM); \
   NOW=$(date +%%s); \
   if [ -z "$ALARM" ] || [ "$NOW" -ge "$ALARM" ]; then \
       
     if [ $(cat /sys/class/power_supply/AC/online) == '0' ]; then
       echo 'On battery'
       
       if [ $(cat /sys/class/power_supply/BAT0/capacity) -lt 50 ]; then      
         echo 'Battery less than 50%'
         # perform hibernation
         echo "suspend-sedation: Woke up - no alarm set. Hibernating..."; \
         systemctl hibernate; \
       else
         # put it to sleep once again
         systemctl suspend; \
       fi
       
     else
       # echo 'On AC power'
       systemctl suspend; \
     fi   
       
   else \
     echo "suspend-sedation: Woke up before alarm - normal wakeup."; \
     /usr/sbin/rtcwake --auto --mode disable; \
   fi \
   '
       
   [Install]
   WantedBy=sleep.target
   

   Move the script to the proper directory:

   mv /tmp/suspend-sedation.service /etc/systemd/system/suspend-sedation.service
   

2. DEPRECATED Original version

   # ## MB note: 
   # ## file created in order to enable suspend-then-hibernate
   # ## according to https://wiki.debian.org/SystemdSuspendSedation
       
   # /etc/systemd/system/suspend-sedation.service
   [Unit]
   Description=Hibernate after suspend
   Documentation=https://bbs.archlinux.org/viewtopic.php?pid=1420279#p1420279
   Documentation=https://bbs.archlinux.org/viewtopic.php?pid=1574125#p1574125
   Documentation=https://wiki.archlinux.org/index.php/Power_management
   Documentation=http://forums.debian.net/viewtopic.php?f=5&t=129088
   Documentation=https://wiki.debian.org/SystemdSuspendSedation
   Conflicts=hibernate.target hybrid-sleep.target
   Before=sleep.target
   StopWhenUnneeded=true
       
   [Service]
   Type=oneshot
   RemainAfterExit=yes
   Environment="ALARM_SEC=1800"
   Environment="WAKEALARM=/sys/class/rtc/rtc0/wakealarm"
       
   ExecStart=/usr/sbin/rtcwake --seconds $ALARM_SEC --auto --mode no
   ExecStop=/bin/sh -c '\
   ALARM=$(cat $WAKEALARM); \
   NOW=$(date +%%s); \
   if [ -z "$ALARM" ] || [ "$NOW" -ge "$ALARM" ]; then \
     echo "suspend-sedation: Woke up - no alarm set. Hibernating..."; \
     systemctl hibernate; \
   else \
     echo "suspend-sedation: Woke up before alarm - normal wakeup."; \
     /usr/sbin/rtcwake --auto --mode disable; \
   fi \
   '
       
   [Install]
   WantedBy=sleep.target
   

Enable it with

sudo systemctl enable suspend-sedation

Customizing suspend-then-hibernate

Tests for preparing version with hibernating only if battery is low and laptop is not on ac power

  #!/bin/sh
  cat /sys/class/power_supply/AC/online
  cat /sys/class/power_supply/BAT0/capacity

# if [ $(cat /sys/class/power_supply/AC/online) == '0' ]; then
#     echo 'On battery'

#     if [ $(cat /sys/class/power_supply/BAT0/capacity) -lt 50 ]; then      
#       echo 'Battery less than 50%'
#       # perform hibernation
#     fi
# else
#     echo 'On AC power'
# fi