[pulseaudio-discuss] cannot control input devices from pavucontrol + crashes in recording tab

[Colin Guthrie]

'Twas brillig, and Peter Hercek at 28/12/10 19:58 did gyre and gimble:
> Yes, it is quite usable for me. But the main reason is that I almost
> always run an image in virtual box which keeps one connection always
> active when it runs.
> 
> I can run it without x11-publish and if I do not mess with it will work
> fine ... till I do not start some other application using the pulseaudio
> server. I did more tests and looks like any application (excepet the
> line-in loopback itlsef) using the server will make it exit 20 seconds
> after it is finished. This is even when I do not have suspend-on-idle
> loaded.
> 
> I thought the only expection is pacmd which would cause the server to
> exit immediately. I was wrong. I used command exit as a way to quit
> pacmd but that tells the server to exit too. When I finished pacmd with
> ^D it behaved as all the rest of the pulseaudo server clients.
> 
> My hypothesis would be that x11-publish somehow uses the server which
> starts the 20 sec countdown. The rest of the modules I have loaded do
> not do this. Any apllication connecting the server starts 20 sec
> countdown too (when it finishes). Loopback cannot keep the server used
> (so I think it should keep it used if it is not muted).
> 
> As for as the module-x11-xsmp. I do not use it. I also to not use any
> desktop environment. I have only the bare xserver, fluxbox, and a few of
> x11 apps installed. Minimalistic environment, nothing fancy.


Ahhh, right, then this last bit is the telling thing. This is
technically expected behaviour. PA only stays alive when it's needed. It
considers itself "needed" when an external client connects. e.g. some
application that uses PA in some capacity.

When no application has expressed and interest in using PA for 20s, then
it exits. This is intended behaviour and is what the setting
exit-idle-time in daemon.conf (see "man pulse-daemon.conf" for details)
controls.

Normally, PA will be kept alive for the duration of the user's X11
session by loading a special PA module (module-x11-xsmp) to connect to
the X11 Session Manager. It allows PA to stay alive and not exit for the
duration of the X11 session. If you do not run a session manager,
obviously this module in PA cannot be loaded and PA will exit after 20s.

Now you could argue that module-loopback should actually prevent idle
timeout. I'd be tempted to agree with this, but there are probably other
folk that would say that's a bad idea as it's often a "hidden" feature
and we'd have people asking why their PA server is not exiting after the
timeout!


As for an immediate exit when used in combination of module-x11-publish,
can you confirm that this immediate exit was just due to you manually
telling the server to exit by typing "exit" into pacmd?

If so, then things are all working as expected (albeit with the
module-loopback not preventing an idle timeout of the daemon which
should likely be addressed somehow - likely a relatively simple patch to
module-loopback.c).

Col



-- 

Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/

Day Job:
  Tribalogic Limited [http://www.tribalogic.net/]
Open Source:
  Mageia Contributor [http://www.mageia.org/]
  PulseAudio Hacker [http://www.pulseaudio.org/]
  Trac Hacker [http://trac.edgewall.org/]