Linux

Okay, killed by Ubuntu is an exaggeration, as Ubuntu is not the only Linux distro doing this.

Still, the big news is that Linux Mint is bringing hibernation back.

In a recent blog post, the Mint team previewed a new Sleep Modes page in the System Administration tool. It's meant to make enabling hibernation and setting it up correctly easy, without you editing config files by hand. The feature is planned for the upcoming Mint 27 release coming in December.

Mint hasn't magically fixed the problems that made Ubuntu drop hibernation. What it does is give you the choice, along with two hybrid modes that sit between suspend and hibernation.

Hibernation vs suspend: What's the difference?

Both features are about saving your session, which simply means everything you have open like your apps, windows and documents.

When you suspend (also called sleep), your computer keeps your session in RAM and powers down almost everything else. Waking up takes a couple of seconds. The catch is that RAM needs power to hold that data, so a suspended laptop keeps draining its battery.

If the battery dies while suspended, your session is lost, along with any unsaved work.

Hibernation copies your session from RAM to your disk and then powers off the machine completely. It uses no power at all. When you turn the computer back on, the session loads back from disk and your apps and windows are exactly where you left them.

In short, suspend is fast but needs power. Hibernation is slow but survives a dead battery.

Why Ubuntu and other distros dropped hibernation

Ubuntu disabled hibernation by default back in Ubuntu 12.04, I think. The reason was that it was unreliable slow, and that having two suspend modes confused people.

Every Ubuntu-based distro, including Linux Mint, inherited that decision. Actually, it's not just Ubuntu. Many other Linux distros also do not offer hibernation option anymore.

Speed is indeed a problem. Writing gigabytes of RAM to disk and reading it back can take longer than a full reboot, especially on older hard drives.

Hibernation also needs a lot of swap. Your swap space has to be at least as large as the RAM in use so the whole session fits. Ubuntu ships a small swap file by default, and Fedora uses zram, which lives in RAM and is useless for hibernation.

Then there's Secure Boot. With Secure Boot enabled, the Linux kernel runs in lockdown mode, and lockdown blocks hibernation because the saved image on disk isn't signed and could be tampered with.

Since most new computers ship with Secure Boot on, hibernation simply doesn't work for a large chunk of users. This is one of the main reasons Fedora Workstation doesn't offer hibernation out of the box either.

The three sleep modes in Linux Mint

The new Sleep Modes page gives you three options. You pick the one that suits how you use your computer. You can enable all of them and choose which one to use from the power menu (at least that's what it looks to me).

New sleep modes in Linux Mint 27

Hibernation

This is the classic mode. Your session is saved to disk and the computer shuts down completely, using no power. It's slower than suspend and can take longer than a reboot to hibernate and resume.

Hybrid Sleep

Hybrid Sleep suspends your computer and saves the session to disk at the same time. Most of the time, you get the quick wake-up of suspend. If the battery runs out, you'll need to plug in the charger, but your session is still there to resume from disk.

Suspend-then-Hibernate

This one suspends first and switches to hibernation only when the battery level gets critical. I think this is the most practical option for laptop users. You get fast resume in normal use and a safety net when the battery is about to die.

What Mint's new sleep mode doesn't fix

None of this removes the old limitations. You still need plenty of swap, and the tool flags a lack of swap as a problem. If Secure Boot is enabled, the tool lists it under Detected Problems. The good thing is that the tool writes its settings to its own systemd file, so you can turn these modes on and off without messing up your system.

I like how Mint takes a subtle approaches to "new features". Not every new feature needs to have AI in it. This is not a shiny new change but it's one of those changes that everyday Linux users are likely to use. Am I right?