Headless output

[robbins]

Does Niri have the ability to create headless outputs that aren't tied to any physical monitor? e.g. for programs like Moonlight/Sunshine?

e.g. https://wiki.archlinux.org/title/Sway#Create_headless_outputs

[YaLTeR]

Not at the moment.

[djmaze]

Not only for that, it is also needed for virtual desktops in VR / MR (which I am planning to do in the future). People reported successfully using headless outputs in Hyprland for use in the Immersed virtual desktop environment.

I have no deeper knowledge about this topic, but this sounds to me like the used smithay toolkit already somewhat supports these kind of usecases: Smithay/smithay#287

[YaLTeR]

I don't think anything is missing on the Smithay side for headless outputs.

[djmaze]

Talking about immersed, I just tried running it (on NixOS). On sway it works, but on niri it fails to start, outputting this message:

listener function for opcode 2 of wl_output is NULL

What could be the reason? Is this maybe a client problem as similarly reported here?

[djmaze]

Ah yes, client problem, just found this: pop-os/cosmic-epoch#1137

[FlyingWombat]

If you make support for headless output, please consider including a way to detach an existing session from its display and make it headless. A use case for this is starting a VM with VFIO gpu passthrough, without having to kill the user session.

[YaLTeR]

Interesting use case, could you link some more info about it?