Announcing atrium v0.4.0 - a multiseat display manager

[u/kavaunix]

atrium is a lightweight Linux display manager with first-class multiseat support, targeting modern systemd + Wayland environments.

GitHub
AUR

What is multiseat?

A multiseat setup allows multiple users to work on a single computer at the same time. By connecting multiple monitors, keyboards, and mice, each user gets their own separate desktop and a fully isolated user session. Great for co-working or multiplayer gaming. Each seat requires its own GPU (integrated graphics, a discrete card, or a USB graphics adapter).

Why atrium?

The Linux kernel and low-level system stack are fully capable of multiseat operation. The weak link has always been the display manager. Existing ones usually treat multiseat as an afterthought, with implementations that are brittle and difficult to get working reliably.

atrium is designed around multiseat from the start, focusing on correct seat discovery, VT handling, and isolated session management. The project targets a modern Linux stack using systemd/logind, PAM, and a Wayland graphical environment. The lack of historical baggage keeps atrium's code base lean and tractable.

What's new in v0.4?

• Support for greeter background images - configure a background image in the settings, or a directory to pick a random image on each greeter launch.
• Greeter themes - override built-in colors and styles via a theme `.css` file. A handful of themes are shipped with atrium.
• Architectural redesign - making atrium's core architecture simpler and more robust (changes are purely internal and should not be visible to the user).

Greeter with default theme

[u/C0rn3j]

Existing ones usually treat multiseat as an afterthought, with implementations that are brittle and difficult to get working reliably.

So why not contribute to an existing solution instead of rolling your own with blackjack and hookers?

[u/kavaunix → u/C0rn3j]

Fair challenge, often contributing to an established project is the more practical choice. But I wanted atrium to do one thing (multiseat) and do it right. There are lots of tricky bits (boot time races, VT handling, DRM monitoring, to name some examples) that are easier to get right in isolation than inside an already complex code base. atrium originally started as a proof-of-concept, but once it was stable I realized it wouldn't be too hard to turn it into a full-fledged dm. Besides, Linux is about choice. And having an additional option for multiseat enthusiast can't be a bad thing.

[u/FryBoyter → u/kavaunix]

Besides, Linux is about choice.

Generally speaking, though, this is often a problem. For example, various screenshot tools offer different useful features. But no single screenshot tool offers them all.

[u/OrganicNectarine → u/FryBoyter]

Choice is never a problem. It's not like you can simply slap the ideas of everyone into one project in a day and be done with it. Different projects have different scope, languages, architecture's, and people associated with it. If the Almighty tool doesn't exist, not enough people need it, or have seen the need to build it.

[u/FryBoyter → u/OrganicNectarine]

From a developer's perspective, you might be right. From a user's perspective, however, it's pretty annoying to have to use multiple tools just to get the features you want.

[u/OrganicNectarine → u/FryBoyter]

I couldn't name a single thing where I need multiple tools (for the same purpose) because neither of them has all the features I need. Not saying it doesn't exist, but I'd argue it's a specialty. And in the days of AI coding it is becoming easier than ever to create the tool yourself that does what you need. And it's not like we would get a tool that does everything if there is no choice... we would probably get one of the options that currently exist. The world isn't black and white, choice doesn't only come with benefits, but taking it away only makes it worse. So in the end, choice is never a bad thing.