Bug 1227873

Summary:	lightdm doesn't respawn X-Server when it was terminated / dm-tool accepts arbitray "display numbers"
Product:	[openSUSE] openSUSE Distribution	Reporter:	Rainer Kaluscha <rainer.kaluscha>
Component:	X11 Applications	Assignee:	E-mail List <screening-team-bugs>
Status:	REOPENED ---	QA Contact:	E-mail List <qa-bugs>
Severity:	Minor
Priority:	P5 - None
Version:	Leap 15.6
Target Milestone:	---
Hardware:	x86-64
OS:	Other
Whiteboard:
Found By:	---	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description Rainer Kaluscha 2024-07-15 20:25:06 UTC

In contrast to sddm, lightdm doesn't respawn a new X-Server when the old one terminated, eg. due to pressing Ctrl-Alt-Backspace twice.

Restarting the lightdm or xdm service is not an option on a multiseat system as this kills all other sessions as well.

As a workaround you can start an X-Server manually and add it with: 
dm-tool add-local-x-seat <display-number>

Unfortunately, the documentation of dm-tool ist not precise. It took me quite long to figure out that <display-number> must not be preceded with a colon, .i.e. use '1' instead of ':1'. Furthermore, dm-tool accepts arbitray "display numbers", e.g. xxx, without complaining that no X-Server was found for that display.

Comment 1 Rainer Kaluscha 2024-07-18 17:26:00 UTC

Now lightdm does respawn a new Xserver - I don't know what has changed ...

Comment 2 Rainer Kaluscha 2024-07-18 17:38:08 UTC

Now I could solve the riddle: If the Xserver ist terminated before user login, it is not respawned and I'm left with a blank screen. If a user logs in and kills the Xserver a new one is respawned. Strange ...