Bug 26591 - Some software does not follow pavucontrol fallback when switching sound card
Summary: Some software does not follow pavucontrol fallback when switching sound card
Status: NEW
Alias: None
Product: Mageia
Classification: Unclassified
Component: RPM Packages (show other bugs)
Version: 7
Hardware: All Linux
Priority: Normal normal
Target Milestone: Mageia 8
Assignee: All Packagers
QA Contact:
Depends on:
Reported: 2020-05-05 11:10 CEST by Cyril Levet
Modified: 2020-09-05 11:29 CEST (History)
1 user (show)

See Also:
Source RPM:
Status comment:

Plasma_Volume (85.58 KB, image/png)
2020-09-04 23:11 CEST, Aurelien Oudelet

Description Cyril Levet 2020-05-05 11:10:43 CEST
Description of problem:

The computer has two different cards for sound output :
- Speakers are plugged on a Xonar Essence STX II sound card
- headphones are plugged on the motherboard (front jack)

When the headphones are plugged, the sound works well. When I start the speakers and unplug the headphones the "falllback" option on pavucontrol is correctly switched to the speakers. However some software does not follow the fallback and try to use the (now unplugged) headphones. I have noticed that at least VLC, Firefox and the system sound of gnome does not use the right output. On the other hand, Skype works well when I switch the output.

If I check the "Playback"on pavucontrol I see that AudioIPCServer stay on the headphones and does not follow fallback control.

A workaround is to go on GNOME parameters and manually switch the output to any other output devices and return to the correct one. If I do this, the new output is correctly handle by Firefox or VLC.

Of course journalctl does not catch any error.

I have a similar bug in another computer with KDE/Plasma DE. But I'm not sure it is related. In this case the problem arises when switching output from HDMI (on a graphic card) to  Internal computer sound (on the motherboard). The fallback does not correctly follow the unplugging of HDMI cable in VLC and Firefox (but works with Skypr).

Of course, the same problem arises if I do the reverse action (speakers on, plug headphones, sound on Firefox stay on the speakers and does not go on headphones).

I think this bug is related to the switch of output cards (sound card/motherboard)

How reproducible: Alwas with Firefox, VLC and Gnome system sounds

Steps to Reproduce:
1. Plug headphones on front jack connected to motherboard and check they work well
2. Play sound with Firefox or VLC and check you can hear it on headphones
3. Turn on speakers plugged on a sound card (not the motherboard)
4. Unplug headphones
5. Sounds on Firefox or VLC continue to be directed to the unplugged speakers.
Comment 1 Lewis Smith 2020-05-07 20:51:56 CEST
Thank you for reporting this. What is expected to happen with two sound outputs is beyond my ken.

Assigning this globally, with no idea what *should* happen, nor where the responsibility lies - pavucontrol or some other sound package, or the user applications.
FWIW pavucontrol has no maintainer.

CC: (none) => lewyssmith
Assignee: bugsquad => pkg-bugs

Comment 2 Aurelien Oudelet 2020-09-04 23:11:34 CEST
Created attachment 11865 [details]


Have you ever tried to add a virtual output like attached screenshot?

Suggestion: Use a virtual output that play simultaneously sound to all sound cards.
Aurelien Oudelet 2020-09-04 23:14:41 CEST

Target Milestone: --- => Mageia 8

Comment 3 Cyril Levet 2020-09-05 11:29:30 CEST
Thank you for the work around. It works well. However it is not always the desired behaviour. When I plug my TV on my computer, I want sound only on TV not both on internal speaker and TV. 
It's not a very annoying bug because I can switch manually.

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