Comment 3 for bug 1956147

This is not my system, so I cannot debug a lot.

Linux kernel 5.4.x is used, and Linux logs hci related messages, and bluetoothd also segfaults. (Ubuntu noticed the crash, and should have uploaded the resulting dumps.)

What fixed it was using `a2dp.py`:

```
$ curl "https://gist.githubusercontent.com/pylover/d68be364adac5f946887b85e6ed6e7ae/raw/install.sh" | sh
  % Total % Received % Xferd Average Speed Time Time Time Current
                                 Dload Upload Total Spent Left Speed
100 314 100 314 0 0 664 0 --:--:-- --:--:-- --:--:-- 670
  % Total % Received % Xferd Average Speed Time Time Time Current
                                 Dload Upload Total Spent Left Speed
100 11977 100 11977 0 0 27402 0 --:--:-- --:--:-- --:--:-- 27470
a2dp installation was successfull.
Run a2dp.py [-h/--help] and enjoy the HiFi music!
$ a2dp.py
Connection MADE
Selecting device:
1. XXX
2. XXX
3. 14:C1:4E:99:XX:XX Office speaker
4. XXX
5. XXX
Select device[1]:
3
Device MAC: 14:C1:4E:99:XX:XX
Device ID: bluez_card.14_C1_4E_99_XX_XX
Sink: bluez_sink.14_C1_4E_99_XX_XX
Updating default sink to bluez_sink.14_C1_4E_99_XX_XX
Setting the off profile
Disconnecting the device.
Connecting again.
Device ID: bluez_card.14_C1_4E_99_XX_XX
Setting the a2dp profile
Updating default sink to bluez_sink.14_C1_4E_99_XX_XX
Ignoring: Command: pacmd list-sink-inputs | grep "index:" failed with status: 1
stderr:
Exiting bluetoothctl
"Enjoy" the HiFi stereo music
```