Multiple pointer / multi-seat support

[rektide]

Back on X, there was multi-pointer support support, MPX, that allowed multiple people pointing devices & their associate other input devices (multi seat) to work on a desktop. I could share a large monitor with a friend or have a second screen for them.
https://en.wikipedia.org/wiki/Multi-Pointer_X

This sounds super daunting to add and it's not common to how folks users computers today, but I am opening this ticket to at least raise the possibility. Many thanks for the excellent Wayland server.

[YaLTeR]

We're not doing multiseat because it's not practical. No client handles it and it's a very niche use case in general if it is even useful at all

[rektide]

In MPX multi-seat was still useful even when the apps had no support: each cursor had it's own active window and all of the input for that cursor went to that window.

But I hear what you are saying: it is indeed a niche use case.

I will mention that SDL now supports multi-seat! For folks playing local co-op/split-screen video games, this would be a lovely feature to have.
https://www.phoronix.com/news/SDL-Merges-Wayland-Multi-Seat

[Jak2k]

There is some support in tldraw. Support for this feature is a chicken or the egg dilemma and it would definitely be very cool, especially for games or collaborative apps.

[blinry]

For context: I published a blog post on the state of multi-seat Wayland today, along with prototypes of example applications – a collaborative text editing widget, and a multiplayer physics playground. Indeed, @Jak2k, it's a bit of an chicken-and-egg type situation. But I was surprised to find that both sway and River support multiple (logical) seats pretty well out of the box.

Back in January, I made a "quick and dirty" patched version of niri for myself that adds a second seat! Just to demonstrate what it would look like:

niri.mp4

Currently, my patched version is pretty horrible: It only supports two seats, and there are some hardcoded device names in the code. Adding a proper "seat manager" would be the next step. But I thought I'd drop it here in case it inspires someone. :)

[rgambord]

I also am interested in this functionality for a multi-monitor setup where one monitor is a desktop computer and the other is a TV in another room. I already have scripts to move workspaces between monitors so that I can manage what is playing on the TV from my desk, and I can easily move games or video content between the two monitors. This allows me to avoid the hassle of running a separate PC for the TV and gives the benefit of hot swapping between the two setups.

The next thing on my checklist is having a mouse and keyboard that only interacts with my desktop monitor, and a controller setup that only interacts with the TV monitor.