Pipewire for multiple users

[Lucio Crusca <lucio@sulweb.org>]

I'm on Debian bookworm/sid. Until a few days ago I had Pipewire 0.3.32 
from experimental and it used to work for both of the users I have in my 
system as a PulseAudio drop in replacement (thanks to 
pipewire-audio-client-libraries package). Then I accidentally removed it 
and reinstalled it, but 0.3.33 is available now and it works only for 
one of my users (namely "lucio"). For the other user (namely "u") I only 
get:

lucio@t470:~ $ su - u
...
u@t470:~ $ pactl info
Connection failure: Connection refused
pa_context_connect() failed: Connection refused

and user "u" gets no sound. I've also tried logging in as "u" from 
lightdm instead of the terminal, but I get the same results.

With 0.3.32 I had this configuration in 
/etc/pipewire/pipewire-pulse.conf, in order to let other users play sounds:

[...]
context.modules = [
    [...]
    {   name = libpipewire-module-protocol-pulse
        args = {
            server.address = [
                "unix:native"
                "tcp:4713"
            ]


That file is still there on my system, because it was there for the 
0.3.32 version and no one deleted it, but when I tried to follow these 
steps [1] again, hoping to fix the problem, I noticed that 0.3.33 does 
not bundle example configuration files anymore, or, at least, they are 
not in the directory specified by the documentation anymore. So I 
suspect something changed between 0.3.32 and 0.3.33 as far as the 
configuration is concerned, but I'm not sure.

Please also note that "u" user not only lacks a functioning PA 
replacement, but even ALSA and JACK replacements are not working anymore.

The systemctl command for the "u" user bails out with

Failed to connect to bus: No such file or directory

but I'm not sure I actually need to execute systemctl commands for the 
"u" user while running "inside" the "lucio" session (xhost +)... I seem 
to recall it used to work without them, just with the "tcp:4713" config 
in place, but things may have changed with the new release, so I thought 
it could be useful to add this piece of information.

Any thoughts?

[1] https://wiki.debian.org/PipeWire