Today I learned about `loginctl` which, as expected, controls Linux logins. It's not quite as well documented as I'd like, but after tinkering with it for a while I've done some very cool stuff.
I put two NVidia cards into a 2U server and used `loginctl` to associate each one with an automatic login session in lightdm (plus one non-autologin session with the built-in VGA hardware). So without creating an xorg.conf at all, this system runs an X session for each card plus Steam to stream games!
[email protected]:~$ loginctl seat-status seat1
│ [MASTER] drm:card1
A little group