Broken Audio infrastructure on Kubuntu 17.04

[Aurelijus Rinkevicius]

As of Kubuntu 17.04, KDE sound infrastructure is broken.
Issue:
    * System Settings -> Audio and Video -> Audio Playback. Reports "PulseAudio Sound Server" as your device of preference.
    * Sound does not work with multiple sound devices (there is a workaround though).

Comments:
    1. Such a problem can occur if one restarts PA or settings are wrong.
    2. Problem persists on both kubuntu-17.04-desktop-amd64.iso (running live) and on an updated system (tried on two different machines with consistent results).
    3. Problem is *not present* with KDE neon (neon-useredition-20170413-1018-amd64.iso)
    4. Problem was *not present* with Kubuntu 16.10

$ lsb_release -rd
Description: Ubuntu 17.04
Release: 17.04

[Ubuntu Foundations Team Bug Bot (crichton)]

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[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[zyrorl (zyrorl)]

I can confirm that this very annoying bug is affecting me, as I now have to constantly enable/disable audio sources to switch audio devices rather than use phonon's priority list.

[Stefano Pettini (ragazzojp)]

I can confirm this bug as well. After a brief investigation, it looks like PulseAudio is started properly, but Phonom audio routing doesn't use it fully. Many pages mention something about "starting pulseaudio and routing KDE to is".

It looks like there are two scripts to start pulseaudio:

start-pulseaudio-x11
start-pulseaudio-kde

The second one should also enable the proper audio routing, so devices show up properly instead of having one single entry for "PulseAudio Sound Server".

Unfortunately the script start-pulseaudio-kde is not part of the system and I can't find it anywhere. I can only find start-pulseaudio-x11 in my system.

[Aurelijus Rinkevicius (odysei)]

Interestingly, I cannot find start-pulseaudio-kde in neither Kubuntu 16.10, nor KDE Neon.

[Stefano Pettini (ragazzojp)]

Right, the bug is probably not because of that missing script, but that script may provide some hints on the kind of setting or audio routing feature that is not properly enabled.

I remember doing some tests about bluetooth devices in the past on 15.10: the system was working properly, but every time I restarted pulseaudio (so basically when I restarted it, instead of when it was started by the system), the integration didn't work properly and I saw in the audio device list "PulseAudio Sound Server". I had to reboot to fix it.

So we have two hints in the same direction: after starting pulseaudio, something must be done to enable proper integration with KDE. Something that doesn't happen in Kubuntu 17.04.

[zyrorl (zyrorl)]

Any updates on this? this is a pretty frustrating issue as it doesn't allow us to properly prioritise sound sources in KDE with multiple sound cards.

[Aurelijus Rinkevicius (odysei)]

It looks like that we are dead in the water on this. Soon it will be a time to move to a better maintained distro.

[José Tomás Atria (jtatria)]

This bug is caused by module-device-manager not being loaded when pulseaudio starts. This command fixes the issue and restores pulseaudio KDE integration:

$ pactl load-module module-device-manager "do_routing=1"

This command is included in the pulseaudio startup script for X11, /usr/bin/start-pulseaudio-x11, which is included as part of the XDG autostart scripts via a reference in /etc/xdg/autostart/pulseaudio.desktop. As far as I understand the FreeDesktop standard, .desktop files in the /etc/xdg/autostart folder should be executed by the desktop manager on startup, which in the case of KDE is controlled by the script located at /usr/bin/startkde, but the version shipped by Kubuntu does not seem to make any reference to /etc/xdg/autostart files.

I have tested that /usr/bin/start-pulseaudio-x11 is not being ran on startup. I have no idea how KDE is starting pulseaudio, and since pulseaudio is part of the poetteringverse, determining its execution model or startup sequence is beyond the comprehension of mere mortals; but lack of integration between pulseaudio and phonon (the audio system settings module) is due to that module not being loaded, due to that script not being ran, due to, I assume, KDE not executing XDG autostart desktop files.

[Petr Sedlacek (piit79)]

José, thanks for pointing out a workaround!

I haven't had time to confirm yet but I may have found the reason the script /usr/bin/start-pulseaudio-x11 wasn't running correctly on my system. When I tried executing it manually I got the error message "Failed to open sound file." Looking at the script it contains the line

/usr/bin/pactl upload-sample /usr/share/sounds/ubuntu/stereo/bell.ogg bell.ogg > /dev/null

However, the file /usr/share/sounds/ubuntu/stereo/bell.ogg wasn't present on my system. Since the script is run with sh -e it will stop on the first failure and therefore not load module-device-manager. I found out that the sound file is part of the package ubuntu-sounds - once installed, the script runs correctly.

José, could you please check if you have the package ubuntu-sounds installed? The description says "Ubuntu's GNOME audio theme" so no wonder it's not installed by default on Kubuntu. This therefore seems to be a packaging bug in pulseaudio - the package should depend on ubuntu-sounds.

[Petr Sedlacek (piit79)]

I just reported a bug in pulseaudio related to the above - could you please check if that's the case for you as well and confirm that the bug affects you too? Thanks!

[Petr Sedlacek (piit79)]

Apologies for another message and notification... forgot the link to the bug:
https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1703334

[José Tomás Atria (jtatria)]

Hi Petr, thanks for looking into this. I did not have ubuntu-sounds installed, and I can confirm that installing that package fixes the issue in my system.

I'll add a comment to the new bug with this info.

[Aurelijus Rinkevicius (odysei)]

Awesome guys!

Jose: thanks for the pactl command, I was looking for this one since ages. Once in a while I crash/restart pulseaudio and KDE audio gets stuck.

Petr: the solution did work! Now we're just missing a pulseaudio fix in the repos.

[Proc (proc)]

Similar problem here.
My headphones are always "unplugged" according to pavucontrol.
I can switch around my alsamixer settings all the way I want, no audio from headphones.
This was working in 14.04 LTS