Do not understand this:

$ pstree `pidof sddm`
sddm─┬─Xorg.bin───7*[{Xorg.bin}]
     ├─sddm-helper───startplasma-way───{startplasma-way}
     └─{sddm}

I did select wayland session, do not understand what those xorg instances are for…

If I interpret this correctly the desktop is running on top of Wayland. Just wondering the purpose of xorg instances.

@jarkko Probably XWayland? If application doesn't have Wayland support they are ran under X session managed by Wayland.

@jarkko If you don't configure the greeter to run in Wayland, it still runs in X11. To the best of my knowledge, @fedora is the only distribution that does this out of the box right now.

@orva I recall seeing in Ubuntu xwayland process as xwayland not xorg but could be wrong because do not have Ubuntu installation available to check :-) And if I recall correctly it should be child process of wayland...

@Conan_Kudo @fedora

Right:

$ sudo cat /proc/2975/environ | tr '\0' '\n'                        
PIDFILE=/run/sddm.pid
PWD=/
SYSTEMD_EXEC_PID=2940
LANG=en_US.UTF-8
INVOCATION_ID=6e2dee533d9f4aab932067246e07ffa8
USER=root
SHLVL=1
WINDOWMANAGER=/usr/bin/startplasma-x11
JOURNAL_STREAM=8:16977
XDG_DATA_DIRS=/var/lib/flatpak/exports/share:/usr/local/share/:/usr/share/
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
_=/usr/sbin/startproc
PREVLEVEL=N
RUNLEVEL=?
DAEMON=/usr/bin/sddm

However:

$
 echo $XDG_SESSION_TYPE 
wayland

So I guess I have two instances of Plasma running, one for SDDM and other for the running session, i.e. the GUI selector for windows manager does nothing the to SDDM itself.

@Conan_Kudo @fedora Actually in my running session also:

$ echo $WINDOWMANAGER 
/usr/bin/startplasma-x11

I’d expect it to be different within the session, does not feel aligned with the value of XGD_SESSION_TYPE but I don’t have deep knowledge of their semantics so I guess I’m lacking some knowledge.

@Conan_Kudo @fedora

With trial and error I got OpenSUSE working with only Wayland. I did first:

$ sudo systemctl disable xdm.service
$ sudo systemctl enable sddm.service

And created a config file:

$ cat /etc/sddm.conf.d/wayland.conf 
[General]
DisplayServer=wayland
GreeterEnvironment=QT_WAYLAND_SHELL_INTEGRATION=layer-shell

[Wayland]
EnableHiDPI=true

Only glitch I see is in systemctl status sddm:

Apr 01 17:58:05 suppilovahvero sddm-helper[2368]: Failed to write utmpx:  No such file or directory

Not sure what kind of side-effects that might have…

@Conan_Kudo @fedora Deleted my own config. It seems to use /usr/lib/sddm/sddm.conf.d/11-kwin_wayland.conf as long as sddm.service is enabled instead of xdm.service.

@Conan_Kudo @fedora that utpm error is weird and does not report where it tries access the accounting db so i just ignore it for now :-) no idea how to tackle the problem right now