Brian J. Murrell wrote:
> Hi all.
>
> I have a bluetooth dongle on a machine with PA 0.9.18 (Ubuntu Karmic) on
> it and a headset paired successfully. From the PA debug (-vvvv) output,
> it appears that PA sees the headset but then removes the bluetooth
> module, for whatever reason:
>
>
The reason PA unloads the BT device module is here:
I: module-bluetooth-device.c: FD error: POLLERR
D: module-bluetooth-device.c: IO thread failed
This is happening because there is some problem setting up a SCO
connection (bluetooth transport protocol specified by headset
profile/hands-free profile) to the headset.
Your options moving forward:
1) Troubleshoot bluez for why the SCO connection is failing. Start
with the very newest bluez (there have been a few audio-related bug
fixes in recent weeks). Debug logging of the user-level daemon (where
much of the audio-related BT support resides) is enabled with:
sudo kill -USR2 [process_id of /usr/sbin/bluetoothd]
and logged to /var/log/daemon.log on Ubuntu. Also running,
sudo hcidump -t -X -V
can be helpful in the diagnostic process (look for the result code in
the "Synchronous Connect Complete" packet and what happens after).
If the above seems like a hassle, that's because it is. Unfortunately,
there is no way via configuration in pulseaudio to have A2DP be the
preferred profile for discovered bluetooth devices (presumably because
HSP/HFP is more common).
2) If you only want A2DP and don't want pulseaudio connecting via
HSP/HFP, you can only do it per-device and must sacrifice BT device
discovery. Comment out the load of module-bluetooth-discover in
/etc/pulse/default.pa and add the following line to the same file
(replace xx:xx:xx:xx:xx:xx below with your headset's BT_ADDR):
load-module module-bluetooth-device address=xx:xx:xx:xx:xx:xx
profile=a2dp
You can do this via the command line as well:
pactl list <-- to find module # of module-bluetooth-discover
pactl unload-module [module# of module-bluetooth-discover]
pactl load-module module-bluetooth-device address=xx:xx:xx:xx:xx:xx
profile=a2dp
3) Modify & build a custom version of pulseaudio that prefers A2DP
rather than HSP/HFP. Hint: Look at add_card() in
pulseaudio/src/modules/bluetooth/module-bluetooth-device.c. You can
change the profile priority values...
Cavaets:
1) The headset has to already be on when module-bluetooth-device loads
or it selects the off profile.
2) Selecting a different profile can be done with pavucontrol via the
"Configuration" tab or within the quasi-shell pacmd via the
set-card-profile command.
3) pavucontrol 0.9.8 terminates with pulseaudio 0.9.17+. It's looking
for a headset icon that doesn't exist. (you can fake it by stuffing a
audio-bluetooth-headset.svg file in $HOME/.icons).
4) The terminate bug above has reportedly been fixed for a while but
only just released in pavucontrol 0.9.9. pavucontrol 0.9.9 is not yet
packaged for Ubuntu. Good luck if you want to get that working on your
own...
Regards,
Peter Hurley
