[systemd-devel] User bus broke automatic multiseat

[Simon McVittie]

On Wed, 14 Dec 2016 at 23:23:55 +0300, Oleg Samarin wrote:
> 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?

Either don't configure dbus with --enable-user-session, or teach gdm
to create a per-display D-Bus bus for each of its X11 displays (or
Wayland equivalent).

For the former solution, see the split between the dbus and
dbus-user-session packages in Debian. dbus is always configured
with --enable-user-session there, but we split out the user-session parts
(basically /usr/lib/systemd/user) into dbus-user-session_*.deb so that
it's opt-in.

For the latter solution, the patch/script on the Red Hat bug you referenced
are implementations of the right sort of idea. Please talk to the gdm (GNOME)
developers about the best way to integrate that.

    S