I'm trying to create a multiseat setup for two seats, with a monitor, keyboard, mouse, and USB soundcard for each seat. With my primary user logged in, I created a second seat with its own monitor, keyboard, and mouse using loginctl attach as described in https://wiki.archlinux.org/index.php/Xorg_multiseat. GDM started on that seat automatically. I have everything for the second seat plugged into a powered USB hub, and I assigned that hub to the second seat, as recommended in the above link:
It would be more flexible to add a specific USB port to the seat instead, allowing any device plugged into that USB port to be assigned to the seat (keyboard, mouse, USB sound card, etc.) Here, two USB ports are assigned to the seat, which you can see has just come from the same list above with the end part removed:
I logged in as a separate user on on that seat. I can see two pulseaudio processes running, one for each seat, and I'm using the system default pulseaudio configuration for both users. If I do "loginctl seat-status seatnew", I see all devices plugged into that second hub listed as expected, including the audio device. When I unplug my USB audio device, and then plug it back in, it seems that both of the pulseaudio processes try to grab the device with their udev module, instead of just the one whose user is logged in at that seat.
I would expect Pulseaudio's udev module should be paying attention to the ID_SEAT, which I verified was assigned properly to the second seat using udevadm info. Why is the wrong pulseaudio process sometimes picking up the audio device plugged into the second seat USB hub?
