PulseAudio Restart Bug – Solved

I enjoy my Linux computers, and one reason is the fact that many technical issues can be resolved, without having to reboot endlessly. However, in my past usage, there has been an irritating exception to this pattern. It’s common under Linux, that we can simply restart the PulseAudio Server from the command-line, using one out of several methods, and that the subject should be done with. But alas, every time I have ever restarted PulseAudio in this way, or, if the server restarted on its own, afterwards, when looking up the Plasma 5 -generated status display (which is actually referred to as “Phonon”), I’d be missing a Devices List, like so:

Screenshot_20191026_152751

This type of display can be interpreted to mean several things, such as, that the PulseAudio server did restart, but that perhaps, it simply failed to connect to the inter-process, session-unique, message-bus. Therefore, in the past, whenever I had such a display, I eventually did what I thought I had to do, which was, to log out and back in again, or, to reboot. On my system, PulseAudio is configured such, that it runs as one user-name, and not as root.

In fact, a peculiar side effect of this bug was, that the list of available output devices was still being displayed, within ‘pavucontrol‘.

But this ordeal has now become even more inconvenient than it ever was because on the computer which I name ‘Phosphene’, the need may recur more frequently, ‘just to restart the PulseAudio server’.

However, I have finally found the true cause for this malfunction, which was, that when PulseAudio is restarted from within an existing session, it simply fails to load one module, which is also the module that it needs, in order to be able to list the available devices:

 


module-device-manager

 

In fact, there exists a script in ‘/usr/bin‘, that loads a series of X11-related modules.

Therefore, after a restart of this service, I can simply give the following command now:

 


/usr/bin/start-pulseaudio-x11

 

And Eureka! I can now obtain a list of available devices, without ever having to log out and back in, or, without ever having to reboot:

Screenshot_20191026_152853

In fact, I have created a shell-script, which I can click on as user, and which carries out this task, safely.


 

I’ve also discovered that the ‘ProjectM’ music visualization application still works, and detects the beat of the playing music as before. What this means is that theoretically, after ‘ProjectM’ was installed, instead of rebooting, I could have just restarted the PulseAudio server as described here, to get that working.


 

( Edited 2019/10/29, 23h35 … )

I know that there exists an unrelated problem, that just happens to give the same appearance within ‘Phonon’, but that cannot be resolved in this way…

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