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Enabling Hibernate on my Linux laptop (Pop OS)

Or how to keep your battery after closing your laptop.

I’ve been using Linux on my laptop for more than a decade now. It is well-known that depending on the distro and the laptop you use, “deep sleep” and/or hibernate may not be well-supported. This means that even every time that I closed the lid of my laptop, its battery will end up draining until it runs out. This was quite frustrating, because it meant that if I was working on my laptop and closed the lid without remembering to shut down the laptop, I would come back to a laptop without battery.

I recently bought a new Framework computer, and while I was setting it up, I decided that it was long overdo for me go properly configure my laptops so this didn’t happen ever again. After closing the lid of my laptop, I wanted to come back to a device with its battery (almost) intact. And this is how I embarked myself into the adventure of figuring out how to configure hibernate on my Linux distro.


Full context, I am currently running Pop OS (a Debian-based distro created by System76) on all my devices. These steps should definitely work on every Debian-based distro, and presumably also apply to other distros, but let me know if this is the case.

First thing’s first. Before doing anything we should double-check that hibernate is actually supported by our kernel:

cat /sys/power/state

In order to avoid any changes to my disk partitions, I will set up a swapfile to support hibernation, so the above command should list disk in order for our kernel to support the hibernation setup that I will walk you through in this post.

Create a swap file

If you don’t already have a swap partition, or it is not big enough to fit the size requirements to hibernate your system, you’ll need to create a new swap file. As a rule of thumb, your swapfile should have around twice the size of your RAM to ensure that there' s enough space to persist your data for hibernation (but you could also check out this support page for a more accurate explanation). In my case, I have 64GiB of RAM in my laptop, so I configured a 128G swap file through:

  • First, I created the swap file, assigned the right permissions, and formatted as a swap.
sudo fallocate -l 128G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
  • And then activated the swap
sudo swapon /swapfile
echo '/swapfile none swap defaults 0 0' | sudo tee -a /etc/fstab
  • Finally, we can check if the above commands worked by listing the system’s swaps. Your new /swapfile swap should be listed there.
cat /proc/swaps

Configure hibernation

With our swap ready, we are now in a position to configure hibernation in our system:

  • We first need to get the UUID of our new swap file:
findmnt -no UUID -T /swapfile

You should receive an output that is something like 9e29141f-822f-4758-bb9a-87f3eaa6e1a5.

  • We then need to get the swap offset.
sudo filefrag -v /swapfile | awk '{ if($1=="0:"){print $4} }'

The output should be a number such as 9999999...

  • We’ll configure now the kernel swap using the <UUID> and <offset> values from above (replace these in the command below with your own values).
sudo kernelstub -a "resume=UUID=<UUID>"
sudo kernelstub -a "resume_offset=<offeset>"

# Example
# sudo kernelstub -a "resume=UUID=9e29141f-822f-4758-bb9a-87f3eaa6e1a5"
# sudo kernelstub -a "resume_offset=9999999"
  • And adding the following line to /etc/initramfs-tools/conf.d/resume. You should create the file if the file doesn’t already exist.
resume=UUID=<UUID> resume_offset=<offset>
  • Finally, we update our kernel configuration through:
sudo update-initramfs -u

In order to test if this worked you can restart your system, and then run see what happens:

sudo systemctl hibernate

Configure hibernation when closing the lid

Cool! So hibernate works, but how can I configure the system to hibernate after some time when closing the lid so my battery is not drained? Actually this was simpler than expected. We just need to:

  • Edit /etc/systemd/logind.conf to enable suspend-then-hibernate (as you may see in the config below, you can also optionally set this configuration when the lid is closed and there is external power, or when we suspend the device after being idle for some time):
. . .
+ HandleLidSwitch=suspend-then-hibernate
. . .
  • We can configure the delay in seconds for hibernate to kick-in when the system is suspended by editing etc/systemd/sleep.conf as follows (in my case 60 mins):
#SuspendState=mem standby freeze
#HibernateMode=platform shutdown
#HybridSleepMode=suspend platform shutdown
+ HibernateDelaySec=60min

And with this (hopefully), you won’t run out of battery when you close your lid and forget to shutdown your laptop for the day. If you try this, let me know if it works for you. I would love to keep this article as up-to-date as possible, and even add a “workaround” section with all of the “gotchas” that other people may have found. Cheers!


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