Bug#940549: [gdm3] gdm3 seems to not respect x-session-manager since Buster

[Simon McVittie]

On Tue, 17 Sep 2019 at 09:28:10 +0200, Adrien Grellier wrote:
> Plasma is configured system wide as the default session with
> update-alternatives :
> 
> root at pc-lheea182:~# update-alternatives --config x-session-manager
...
> But since Buster, GDM3 launch GNOME as the default session ! We have to
> specify manually Plasma on the first connexion.

Since buster, gdm3 prefers to use the GNOME Wayland session instead of
any X session (GNOME or otherwise).

If you are consistently using Plasma everywhere, I would suggest
installing KDE's preferred display manager instead of gdm. gdm has a
lot of GNOME assumptions.

There is probably a way to configure gdm to select a Plasma session by
default, but I don't immediately know what it is.

    smcv