Bug#845938: pulseaudio: bt headset: a2dp sink is not selectable - only hsp/hfp works

[Antoine Beaupre]

Package: pulseaudio
Version: 10.0-1
Followup-For: Bug #845938

This is still an issue in Debian stretch: the gdm3 package runs
pulseaudio, which takes over the bluetooth device and makes it
impossible for regular users to connect to their bluetooth device
using the hifi A2DP sink. See #805414 for more details on that
side. There's a workaround for gdm3 (disabling the BT sink in gdm), so
I'll leave that aside for now and focus on the basic issue here.

>From what I understand, the whole problem here is that PA doesn't
suspend the BT sink when it's not playing any sounds. Just like ALSA,
when no sound is playing, PA should give up the audio device and allow
other PA daemons to playback on the device. This is not a problem for
regular (ALSA) sound devices because that is correctly implemented
there.

Therefore, I would conclude that the underlying bug here is that PA
doesn't release the BT sink when not playing sound. There are many
bugs reported upstream regarding this issue, but the one I found the
most promising is this one:

https://bugs.freedesktop.org/show_bug.cgi?id=57167

... where an actual piece of code is outlined as being the culprit
here. There's another issue regarding BT sink sync that may be
relevant, although I'm not sure I understand the details here:

https://bugs.freedesktop.org/show_bug.cgi?id=45040

... it may be the other way around...

There is also a more generic upstrea bugs regarding this exact issue:

https://bugs.freedesktop.org/show_bug.cgi?id=92102

There are also 54 bluetooth-related bugs filed against pulseaudio
here, which I haven't thoroughly reviewed:

https://bugs.freedesktop.org/buglist.cgi?quicksearch=product%3APulseAudio%20bluetooth

So I'm not sure where to forward this, but it's certainly something
that should be fixed in pulseaudio, in my opinion.

A.

-- Package-specific info:
File '/etc/default/pulseaudio' does not exist


-- System Information:
Debian Release: 9.0
  APT prefers stable
  APT policy: (500, 'stable'), (1, 'experimental'), (1, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: armhf

Kernel: Linux 4.9.0-3-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_CA.UTF-8, LC_CTYPE=fr_CA.UTF-8 (charmap=UTF-8), LANGUAGE=fr_CA.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages pulseaudio depends on:
ii  adduser                      3.115
ii  libasound2                   1.1.3-5
ii  libasound2-plugins           1.1.1-1
ii  libc6                        2.24-11+deb9u1
ii  libcap2                      1:2.25-1
ii  libdbus-1-3                  1.10.18-1
ii  libgcc1                      1:6.3.0-18
ii  libice6                      2:1.0.9-2
ii  libltdl7                     2.4.6-2
ii  liborc-0.4-0                 1:0.4.26-2
ii  libpulse0                    10.0-1
ii  libsm6                       2:1.2.2-1+b3
ii  libsndfile1                  1.0.27-3
ii  libsoxr0                     0.1.2-2
ii  libspeexdsp1                 1.2~rc1.2-1+b2
ii  libstdc++6                   6.3.0-18
ii  libsystemd0                  232-25
ii  libtdb1                      1.3.11-2
ii  libudev1                     232-25
ii  libwebrtc-audio-processing1  0.3-1
ii  libx11-6                     2:1.6.4-3
ii  libx11-xcb1                  2:1.6.4-3
ii  libxcb1                      1.12-1
ii  libxtst6                     2:1.2.3-1
ii  lsb-base                     9.20161125
ii  pulseaudio-utils             10.0-1

Versions of packages pulseaudio recommends:
ii  rtkit  0.11-4+b1

Versions of packages pulseaudio suggests:
pn  paman        <none>
pn  paprefs      <none>
ii  pavucontrol  3.0-3.1
pn  pavumeter    <none>
ii  udev         232-25

-- no debconf information