From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takashi Iwai <tiwai@suse.de>
Subject: Re: [USB-Audio - PX USB,
	playback] snd-usb-audio: probe of 2-3:1.0 failed with error -22
	after kernel upgrade
Date: Tue, 30 Oct 2018 12:24:24 +0100
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To: Mutz Heuer <mutz.heuer@gmail.com>
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On Sun, 28 Oct 2018 22:00:35 +0100,
Mutz Heuer wrote:
> 
> USB-Audio Connection on Bowers & Wilkens PX Bluetooth Headphones started
> working when upgrading kernel from 4.13 to 4.15 series. Then it suddenly
> stopped working again on newer kernels. The bug report has been generated
> on the latest working mainline kernel 4.15.7. All newer kernels have some
> usb quirks in place, which should fix the playback sample rates to 48 kHz.
> The quirk seems not to be working correctly - it seems to hinder the audio
> system to recognize the USB-device as a sound device.
> 
> The Headphones work on kernels before 4,15.7 when manually configuring
> pulseaudio to a default samplerate of 48 kHz.
> 
> PX Headphones are on the newest firmware level.
> 
> See https://patchwork.kernel.org/patch/10265345/. Dropping that patch and
> recompiling the kernel leads to a situation where alsa and pulseaudio seem
> to to be working again.
> 
> Adding
> 
>       default-sample-rate = 48000
> 
> to /etc/pulse/daemon.conf leads to working headphones.
> 
> Maybe the patch has to be adjusted to newer firmware? A quirk seems to be
> really necessary to avoid the specific patch to daemon.conf.
> 
> 
> More details can be found in
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1773697
> What would be the best way to proceed?

Could you check the latest Linus git tree (or for-linus branch of
sound git tree)?  The workaround for the buggy firmware was already
included there.  Let me know if it still doesn't suffice.


thanks,

Takashi