[solved] Odd behaviour from lightdm

justdanyul · 2024-10-13 00:20:21

Context:

I got a thunderbolt dock with a monitor and keyboard connected to it. And sometimes, I'll connect the thunderbolt cable to my server (which has a thunderbolt capable motherboard in it) to control the machine.

Behavior:

If I freshly boot the server, connected to the dock, I get signal and lightdm starts, I can log into i3 and basically everything works exactly as expected. But, lets then say I exit i3 , which takes me back to lightdm, unplug the machine and leave it there for a few hours. Then, when plugging it back in, I don't get any video signal. The monitor is scanning for signal, but cant find anything.

The weirdest thing is if I stop the lightdm service via ssh, I immediately get signal. If it start the lightdm service again, I loose the signal. The only thing that will give me working lightdm login screen, is to reboot.

Any idea how to progress with this?

Last edited by justdanyul (2024-10-14 08:00:47)

seth · 2024-10-13 08:09:52

Sounds a bit like https://bbs.archlinux.org/viewtopic.php?id=300049
What does the system journal and xorg log(s) look like for the critical timeframe?
(I assume this isn't related to lightdm and simply startx would cause the exact same thing?)

justdanyul · 2024-10-13 11:00:31

Its a all a bit odd. I can see from lightdms logs, that it gets a new sd-bus connection when I plug in the monitor. And I generally cant see anything sinister in the journalctl output or the xorg logs.

I took this as a catalyst to try out Ly. And Ly "just works", so i suspect it has something to do with lightdm which has been purged from my system now

seth · 2024-10-13 12:23:38

nb. that has notorious problems w/ the session bus integration, https://github.com/fairyglade/ly/issues … issue+dbus and will likely result in degenerated sessions at some point.
Since X11 generally seems unaffected, though, it would seem that lightdm tries to setup a bogus output configuration, maybe sth. along https://wiki.archlinux.org/title/LightD … ng_monitor ?

I'd ask myself whether I need any DM itfp or just use an autologin/xinit/screenlocker chain.

Please always remember to mark resolved threads by editing your initial posts subject - so others will know that there's no task left, but maybe a solution to find.
Thanks.

justdanyul · 2024-10-14 08:00:24

seth wrote:

nb. that has notorious problems w/ the session bus integration, https://github.com/fairyglade/ly/issues … issue+dbus and will likely result in degenerated sessions at some point.
Since X11 generally seems unaffected, though, it would seem that lightdm tries to setup a bogus output configuration, maybe sth. along https://wiki.archlinux.org/title/LightD … ng_monitor ?
I'd ask myself whether I need any DM itfp or just use an autologin/xinit/screenlocker chain.
Please always remember to mark resolved threads by editing your initial posts subject - so others will know that there's no task left, but maybe a solution to find.
Thanks.

Thanks for the heads up. I recon I'll just go for autologin + i3lock route.

Arch Linux

#1 2024-10-13 00:20:21

[solved] Odd behaviour from lightdm

#2 2024-10-13 08:09:52

Re: [solved] Odd behaviour from lightdm

#3 2024-10-13 11:00:31

Re: [solved] Odd behaviour from lightdm

#4 2024-10-13 12:23:38

Re: [solved] Odd behaviour from lightdm

#5 2024-10-14 08:00:24

Re: [solved] Odd behaviour from lightdm

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