I had been using multiseat on 22.04 with great success. Two nvidia cards and loginctrl to assign the PCI IDs of those, a USB controller, sound, etc, etc.

Then I upgraded to 23.10 and it stopped working. You get a login screen on both displays. Seat0 works as expected but the secondary seat monitor turns off when I log in, as any user.

The session seems to start though, I just can't see anything.

I've tried:

  • Several versions of the Nvidia driver
  • Forcing Wayland through /etc/gdm3/custom.conf
  • Forcing Xorg through /etc/gdm3/custom.conf

One oddity is that the login session remains running after login. It's c14 here. If I kill it, a new one is spawned and the screen switches to it.

    261 1000 oli   seat0      tty2
    262 1002 katie seat-katie 
    c14  120 gdm   seat-katie
I'm usually pretty resourceful when it comes to fixing my own things but I can't even find logs for the second display server. I'm getting pretty desperate. Any help appreciated.