[systemd-devel] User bus broke automatic multiseat

[Oleg Samarin]

The following change in systemd-226:

systemd now supports the concept of user buses replacing
session buses, if used with dbus-1.10 (and enabled via dbus
--enable-user-session). It previously only supported this on
kdbus-enabled systems, and this release expands this to
'dbus-daemon' systems

totally broke the automatic multiseat with GDM: https://bugzilla.redhat
.com/show_bug.cgi?id=1404849

What configuration options can restore the the old session-bus
behavior?