Bug#793637: [sddm] sddm vs plymouth

[Zhang Jingqiang <zh_jq@outlook.com>]

> > Hello,
> > plymouth-quit.service is "static", whichcouldn't be enabled.
> > It won't "done" without any other service run something equal to
> > "plymouth --quit" (I guess).
> 
> Not sure what you mean... The SDDM .service-file specifying
> After=plymouth-quit.service makes it run after plymouth-quit has been
> executed. Since this is a dependency of SDDM, an attemt to start sddm
> will invoke plymouth-quit first. The Conflicts directive will ensure
> sddm is never started when plymouth-quit is still running. This is
> maybe not necessary, since systemd will probably wait a little for
> plymouth-quit to become "ready", but I added it to be sure about
> Plymouth quitting.
> I just checked, the same logic is used by GDM as well, so this should
> work... And it works here as well (tested in a VM).
> Can you maybe run systemctl list-jobs when sddm is failing to start,
> to see if the job is waiting for something?
No tty is available when waiting for plymouth-quit (5 minutes +, no timeout 
set),  I will check later with log level set to debug.

Thanks