[pulseaudio-discuss] How to disable HFP support of pulseaudio on Ubuntu 14.04 LTS

[Tanu Kaskinen]

(Please avoid HTML emails on mailing lists, thanks.)

On Thu, 2015-05-28 at 10:35 +0000, Joseph Codadeen wrote:
> Hi,
> I am a Ubuntu and audio newbie and I am trying to fix an audio problem
> on Ubuntu 14.04 LTS that affects some tests I am working on.I would
> like to know how to disable the HFP support of pulseaudio.
> ProblemI am trying to get some legacy tests to work on Ubuntu 14.04
> LTS, they already work on Ubuntu 12.04 LTS. I have managed to get all
> but one test passing.
> The test is a HFP audio test, it sends an audio file over bluetooth,
> captures it and dumps it to file using hcidump (--audio), and then
> tests the frequency peaks.
> Looking at the output file (converted to .wav by adding a RIFF header)
> we can see an additional channel embedded into the signal that has no
> frequency and resulting in twice the duration, hence the test fails as
> peaks are missing. Being a HFP file this should have only one channel
> (mono) as it did on Ubuntu 12.04 LTS.
> After a process of elimination we found that pulseaudio is to blame,
> i.e. we uninstalled pulseaudio and the failing test passes.

If the test works without pulseaudio, then apparently you're using some
other way than pulseaudio to do the bluetooth audio streaming. In that
case pulseaudio indeed can interfere with your setup, since pulseaudio
will also manage the bluetooth audio. You can remove or comment out
module-bluetooth-discover from /etc/pulse/default.pa to disable
pulseaudio's bluetooth functionality. Or at runtime you can run "pactl
unload-module module-bluetooth-discover".

I don't know what product you're working on, so I don't know if
disabling module-bluetooth-discover is an appropriate thing to do. If
your "thing" is supposed to work on a regular Ubuntu user's system, you
should do Bluetooth audio streaming with pulseaudio, not with whatever
mechanism the test is currently using, because regular users expect
pulseaudio's bluetooth functionality to work.

> It seems to us that pulseaudio is overriding the HFP support provided
> by oFono and this is causing the problem. I understand HFP support is
> a new feature introduced in pulseaudio rel 3?

No it's not a new feature in 3.0. And ofono is irrelevant for audio if
you're not using bluez 5.

-- 
Tanu