Our Steam Deck review is now live, and it’s massive—almost as big as Valve’s new portable PC. With that in mind, I decided to write a shorter article about the Steam Deck’s implementation of Linux since a lot of Ars Technica readers are interested in that use case.
Our full review goes into greater detail about installing and playing Windows games through Valve’s customized Wine compatibility layer, dubbed Steam Proton. This is the default way to access your favorite Steam games, and as our review explores, that proposition is currently iffy. But that’s not the same as using the Deck as a Linux machine. In this companion article, we’ll explain what’s going on with Valve’s first dedicated Linux PC and what it currently can (and cannot) do.
Donating some Plasma knowledge
As Ars Technica reported last year, the Steam Deck runs on a customized fork of Arch Linux. SteamOS is basically a GUI wrapper that runs on top of Arch Linux, and visually, it splits the difference between Steam’s “Big Picture Mode” and the controller-friendly menus of the Nintendo Switch. If you want to use the Deck primarily as a gaming machine, with access to common Steam features like friends lists, notifications, achievements, and forums, SteamOS delivers. Many of its pages work natively with the Steam Deck’s buttons and joysticks, but some run inside a web browser and can only be manipulated by swiping and tapping the Deck’s screen.
You can “switch to desktop” at any time to use the Deck more like a standard computer running Linux. This option, found in the Deck’s “power” menu, closes the SteamOS GUI and opens KDE Plasma, a popular Linux desktop interface. If you’re unfamiliar with Linux, consider this a baby step into the world of open source operating systems. It largely resembles Windows, complete with a bottom-left button that brings up a Start-like selection of shortcuts, and it comes with Plasma’s crucial “Discover” app.
If you dislike Arch Linux or KDE Plasma for any reason, you can grab your preferred Linux distro and install it on another partition. (The same goes for Windows, which I briefly mention in the full review.) But while running another OS, you’ll lose all of the Steam Deck’s native support for its built-in controls and hardware-specific optimizations. Still, Steam Proton as an initiative works across the Linux ecosystem, so installing a different distro won’t leave you entirely in the dark.
Your quickest path to customizing the Steam Deck’s KDE Plasma interface is to search the online Discover database for self-contained installation packages called “flatpaks.” Chances are good that if a flatpak exists for a native Linux-compatible app, it will not only appear in Discover but also be available as a one-click install on the Deck’s internal storage. Descriptions and public reviews appear alongside each Discover search entry.
If you’d rather use standard Linux command line functions to find and install software, that’s also an option by default… so long as the installs in question are only done with flatpaks.
Decked out in armor
The Steam Deck’s flavor of Arch Linux is covered in armor, meaning that a significant portion of the Deck’s internal storage is set to read-only mode. Valve engineer Lawrence Yang said this has been done to save users from “getting your Steam Deck into a bad state or compromising your data,” and he warned that any installations inside the Steam Deck’s read-only image can be wiped out with any SteamOS system update. During my review period, these updates came on a near-daily basis, and based on my findings, I believe Valve has more of them in store in the short term.
Those who don’t mind disregarding Valve’s warnings, the company said, can write onto the read-only image by entering the following into the Steam Deck’s command line:
sudo steamos-readonly disable
In offering these instructions, Yang was very clear: “Don’t do this unless you know what you are doing.” But once this step is taken, the Steam Deck will accept your every pacman and sudo command.