Bug 1227873 - lightdm doesn't respawn X-Server when it was terminated / dm-tool accepts arbitray "display numbers"
Summary: lightdm doesn't respawn X-Server when it was terminated / dm-tool accepts arb...
Status: REOPENED
Alias: None
Product: openSUSE Distribution
Classification: openSUSE
Component: X11 Applications (show other bugs)
Version: Leap 15.6
Hardware: x86-64 Other
: P5 - None : Minor (vote)
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Reported: 2024-07-15 20:25 UTC by Rainer Kaluscha
Modified: 2024-07-18 17:38 UTC (History)
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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 ...