Comment # 23 on bug 1089287 from Stefan Dirsch

(In reply to Michal Srb from comment #22)
> AFAIK the systemd-logind integration in X server is only meaningful when the
> X server runs with the regular user's permissions inside the user's session.
> This is currently only the case with GDM.
> 
> SDDM starts the X server as root. In this case you can consider the X server
> as a system process. It is not tied to the user session that it displays -
> the same X server may display the greeter and later the user session as well.
> 
> That's why X shows the error:
> 
> > [   840.157] (EE) systemd-logind: failed to get session: PID 2837 does not belong to any known session
> 
> It tries to find session that belongs to its own PID and that fails.
> 
> If -keeptty is not set, X server doesn't even try to use the systemd-logind
> integration. If it is set, it tries and fails.
> 
> What is actually the motivation for adding the -keeptty parameter?

Werner?