bug in the ALSA driver 'snd_usb_audio'

bug in the ALSA driver 'snd_usb_audio'

[GitHub issues - opened]

alsa-project/alsa-lib issue #284 was opened from Konfekt:

Hello,

`journalctl -p err` showed the message

```
pulseaudio[15806]: Most likely this is a bug in the ALSA driver 'snd_usb_audio'. Please report this issue to the ALSA developers.
```

Hopefully this bug tracker reaches the ALSA developers?
Here's more output:

```sh
Nov 15 10:28:58 notebook bluetoothd[1340]: src/profile.c:ext_io_disconnected() Unable to get io data for Hands-Free Voice gateway: getpeername: Transport endpoint is not connected (107)
Nov 15 10:28:58 notebook kernel: Bluetooth: hci0: SCO packet for unknown connection handle 6
Nov 15 10:28:58 notebook kernel: Bluetooth: hci0: SCO packet for unknown connection handle 6
Nov 15 10:28:48 notebook pulseaudio[15806]: mSBC decoding error (-2)
Nov 15 10:14:35 notebook pulseaudio[15806]: Playback too far ahead (4591), drop source 1168
Nov 15 10:14:35 notebook pulseaudio[15806]: Doing resync
Nov 15 10:12:28 notebook pulseaudio[15806]: We were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail.
Nov 15 10:12:28 notebook pulseaudio[15806]: Most likely this is a bug in the ALSA driver 'snd_usb_audio'. Please report this issue to the ALSA developers.
Nov 15 10:12:28 notebook pulseaudio[15806]: ALSA woke us up to write new data to the device, but there was actually nothing to write.
Nov 15 10:12:26 notebook pulseaudio[15806]: Playback too far ahead (4613), drop source 1176
Nov 15 10:12:26 notebook pulseaudio[15806]: Doing resync
Nov 15 09:33:13 notebook pulseaudio[15806]: Playback too far ahead (2931), drop source 744
Nov 15 09:33:13 notebook pulseaudio[15806]: Doing resync
Nov 15 09:32:29 notebook bluetoothd[1340]: src/profile.c:ext_io_disconnected() Unable to get io data for Hands-Free Voice gateway: getpeername: Transport endpoint is not connected (107)
Nov 15 09:32:24 notebook bluetoothd[1340]: src/profile.c:ext_io_disconnected() Unable to get io data for Hands-Free Voice gateway: getpeername: Transport endpoint is not connected (107)
```

Curiously my bluetooth headset switches off in Zoom after around five minutes and can't be reenabled. In the hope that this error message gives a hint.
Attached further alsa-infos.

[alsa-info.txt.yOxa5XAE9C.txt](https://github.com/alsa-project/alsa-lib/files/10020916/alsa-info.txt.yOxa5XAE9C.txt)

Issue URL     : https://github.com/alsa-project/alsa-lib/issues/284
Repository URL: https://github.com/alsa-project/alsa-lib

Bug in the ALSA driver 'snd_usb_audio'

[GitHub issues - opened]

alsa-project/alsa-lib issue #105 was opened from rombru:

Hello,
I'm not an expert in linux systems.
I will try to give a maximum of information.

I've bought Bowers & Wilkins PX7 headphones. They doesn't work using USB on Ubuntu.
Using Ubuntu and bluetooth, or audio jack, the headphones work well. 
Using Windows 10 and USB, the headphones work well.

I d'like too use them with USB on Ubuntu because that recharge them in parallel.

Problems while the headphons are connected :
On Chrome : The videos are played too fast and there's no sound (Youtube & Twitch).
On Firefox : The videos are played too fast and there's a crackling sound (Youtube & Twitch).
On VLC : No sound

I've tried with Ubuntu 20.04 & 18.04.
They are set as default audio device
I've played with PulseAudio and alsamixer (reinstall, mute/unmute, ...)
The headphones are set as fallback in PulseAudio.

Trying to find the issue, i've make some test found on Google :
I've added pcie_aspm=off in GRUB_CMDLINE_LINUX_DEFAULT
Setting devices as default in /etc/asound.conf

--- The ALSA part

I think the problem come from ALSA, i've found the errors :
`Failed to load module "module-alsa-card`
followed few lines later by
`Most likely this is a bug in the ALSA driver 'snd_usb_audio'. Please report this issue to the ALSA developers.`

Output of `journalctl --user -u pulseaudio` is [here](https://gist.githubusercontent.com/rombru/eb4ca14168494e95c62a961f92e91a90/raw/52c93f01b9c617f823308183d32d07f8e9033bc1/journalctl.txt)
Output of `pulseaudio -vvvvv` is [here](https://gist.githubusercontent.com/rombru/eb4ca14168494e95c62a961f92e91a90/raw/52c93f01b9c617f823308183d32d07f8e9033bc1/pulseaudio.txt)
Output of `pacmd ls` is [here](https://gist.githubusercontent.com/rombru/eb4ca14168494e95c62a961f92e91a90/raw/52c93f01b9c617f823308183d32d07f8e9033bc1/pacmd.txt)

Please, tell me if you need something more to analyse the problem.

Issue URL     : https://github.com/alsa-project/alsa-lib/issues/105
Repository URL: https://github.com/alsa-project/alsa-lib