Arch Linux

mastrolindus

Member

Registered: 2023-07-08

Posts: 2

my multiseat configuration broke recently

Hi everybody!

I have 2 amd gpus, the vega 56 and the r480x, and I have successfully managed to use them in a multiseat configuration for at least one year.
I am using kde plasma and SDDM.
All I had to do to make it work was using loginctl and assign the right gpu, keyboard and mouse to seat1.
The only problem was that I could not have 2 wayland seats as that would result in a system crash. However one wayland session + one x11 worked perfectly.

However I just realize that it is now broken and it doesn't work anymore.
I realized only now because for a while I didn't enable multiseat, probably the last time I needed it and it worked was around 2-3 months ago.
I suspect some update in this timeframe broke it.

What I witness now if I switch multiseat on is that I see the second login screen on the second monitor, I can input username and password with the second keyboard/mouse, but then if I click login, I see a black screen and eventually I see also the mouse cursor (that I can move). The first screen/seat works normally.
It happens the same no matter if I use 2 waylands, 2 x11, or 1wayland and 1 x11 seats.

Anybody got a clue what changed in the last couple of months that could have broken it? Or how can I try to find out why it is not working anymore?

Thank you and have a great day!

501st

Member

Registered: 2023-07-24

Posts: 1

Re: my multiseat configuration broke recently

Hey,

Can you check ~/.profile or ~/.bash_profile and .zprofile for any commands that don’t execute properly? See this issue: https://github.com/sddm/sddm/issues/1632

Also downgrading ssdm to 0.19 should also work.

mastrolindus

Member

Registered: 2023-07-08

Posts: 2

Re: my multiseat configuration broke recently

If that was the issue, wouldn't that break the login also when not using multiseat?
without multiseat enabled I can login to any user separately without issues.
The black screen occurs only when logging the second user while multiseat is enabled

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 76,569

Re: my multiseat configuration broke recently

The second display server starts (hence the mouse) but the second session doesn't - which is it (KDE, gnome, xfce, i3, …), are you trying to login as the same user and can you log into eg. an openbox session on the second seat? (which won't get you much of a UI, but the rmb should bring up a popup that you can use to start a terminal or sth.)

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sedlons

Member

Registered: 2024-01-18

Posts: 1

Re: my multiseat configuration broke recently

I have same issue. Probably caused by this: SDDM 0.20.0 fails to create session in multi-seat configuration #1762 .

Downgrade to 0.19 resolved my issue.

I used this version:

pacman -U https://archive.archlinux.org/packages/s/sddm/sddm-0.19.0-9-x86_64.pkg.tar.zst