Bluetooth audio multi-user bug?

On my laptop, I have multiple users. My bluetooth headphones are paired to the laptop. One user logged in previously to kept an app running in the background, while I switched to my user and started working on the laptop. I connected my bluetooth headphones which was previously paired (Bose QC35). My bluetooth settings are all done using the KDE panels. I noticed some strange behaviour:

  • On my user, the headphones refused to work in A2DP mode. Instead, it was constnatly in HFP mode, meaning the audio quality was in mono and terrible, and there was mic input available. I could not get the option to switch it back to A2DP, the option simply wasn’t there.
  • If I switch to the other user, the headphones show up as using A2DP in that user.
  • If I log out from the other user, then the headphones work in A2DP in my user.

This doesn’t seem like the right way that it should be working. I would expect both users to use the same A2DP sink, or HFP, whichever is enabled at one time. I can’t tell if this is a Manjaro bug, a KDE bug, or a pulseaudio bug, or perhaps an issue with my specific configuration, or if I am doing something wrong. I feel that this is most definitely a bug though… multi-user setups in the home isn’t very common these days so I won’t be surprised.

i was wondering if anyone else faced this issue, and if I were to report a bug, where it should go.

I am running Manjaro with KDE Plasma. This is an almost 2 year old install.

You can only (presently) have one A2DP output active per Bluetooth card, as far as I know.

e.g. I can connect more than one headset etc. via bluetooth but only the first connected via A2DP gives the option.

Try switching the other user to HFP and see what happens. :smile:

PulseAudio/Examples/Allowing multiple users to share a PulseAudio daemon - ArchWiki

Normally each system user runs their own instance of PulseAudio and the instance is only accessible by the user running it. This is a security measure which prevents other users from accessing potentially sensitive audio channels such as voice calls. However, there are situations in which it is desirable to isolate an application by running it as a separate user. For example, one may wish to run a web browser as a different user while still being able to listen to audio from the browser while using the primary user account. Another use is to share a Bluetooth headset among multiple system users.

The Archwiki example has been posted to 2 previous discussions about PulseAudio multi-user configuration, but no solution:
Headset only available for one account at a time
Set secondary sound card as default