Hi, I've managed to reproduce a similar issue with KDM. With plymouth enabled, it fails to start an X server under certain conditions. During boot the screen just flickers, and I get only to a console login prompt.
`journalctl -u kdm' contains the following lines: -------------------------------------- 8< -------------------------------------- Apr 24 11:02:07 debian kdm[1041]: X server died during startup Apr 24 11:02:07 debian kdm[1041]: X server for display :0 cannot be started, session disabled -------------------------------------- >8 -------------------------------------- /var/log/Xorg.0.log ends with: -------------------------------------- 8< -------------------------------------- [ 28.887] (II) Module "dri2" already built-in [ 29.022] (EE) NOUVEAU(0): [drm] failed to set drm interface version. [ 29.022] (EE) NOUVEAU(0): [drm] error opening the drm [ 29.022] (EE) NOUVEAU(0): 892: [ 29.022] (II) UnloadModule: "nouveau" [ 29.022] (EE) Screen(s) found, but none have a usable configuration. [ 29.022] (EE) Fatal server error: [ 29.022] (EE) no screens found(EE) [ 29.022] (EE) Please consult the The X.Org Foundation support at http://wiki.x.org for help. [ 29.022] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information. [ 29.022] (EE) [ 29.024] (EE) Server terminated with error (1). Closing log file. -------------------------------------- >8 -------------------------------------- Having in mind that everything works fine with no "splash" kernel command line option, I assumed that KDM starts an X server too early, when plymouth splash screen is still active, and therefor the X server can't access the DRM as it's in use by plymouth. Indeed, `systemctl status kdm plymouth-quit' proved that kdm service was started before plymouth-quit service. I decided to try to postpone KDM startup until after plymouth quits, so I created /etc/systemd/system/kdm.service.d/wait4plymouth.conf with the following content: -------------------------------------- 8< -------------------------------------- [Unit] Wants=plymouth-quit-wait.service After=plymouth-quit-wait.service -------------------------------------- >8 -------------------------------------- Indeed, after that I can't reproduce the issue anymore. So, it seems to be a services' dependency problem. -- Алексей Шилин