Created attachment 104211 [details] dmesg output after connecting monitor DisplayLink used to work on my machine with Neon, But after upgrade of packages in December, connecting monitor shows KDE splash screen or a tty or sometimes it's login screen for a few seconds and after that it turns to blank screen and I can't do anything with the system, even switch to tty (Ctrl+Alt+F1) to try to diagnose it. The only thing that still works is Power button. Pressing it displays normal KDE splash screen for turning off and computer turns off in a few seconds. If a monitor is connected during system boot, this happens in a few seconds after the login screen is shown. This could be an issue with DisplayLink driver, but it works on other 16.04 distributions. I attached dmesg output captured a few seconds after described crash by scheduling it before connecting monitor. Monitor model is ASUSTEK MB169B+ I am using the most recent DisplayLink driver version 1.3.52 and KDE neon user with all packages upgraded. This is really frustrating since this left me without my 2nd monitor when traveling and it used to just work.
Bugs for SDDM are not tracked at the KDE bug tracker. Please report this issue directly to SDDM developers via https://github.com/sddm/sddm/issues