linux-kernel - Re: USB DAC broken since commit bf6313a0ff766925462e97b4e733d5952de02367 (5.10.0-rc5)

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Message-ID: <87bks7leun.wl-tiwai@suse.de>
Date:   Fri, 26 Aug 2022 08:05:04 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Lennert Van Alboom <lennert@...alboom.org>
Cc:     Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: USB DAC broken since commit bf6313a0ff766925462e97b4e733d5952de02367 (5.10.0-rc5)

On Thu, 25 Aug 2022 22:52:02 +0200,
Lennert Van Alboom wrote:
> 
> ------- Original Message -------
> On Thursday, August 25th, 2022 at 12:58, Takashi Iwai <tiwai@...e.de> wrote:
> > 
> 
> > There are lots of workarounds for the buggy USB audio firmware, and
> > the latest kernel allows to enable the quirks via quirk_flags module
> > option of snd-usb-audio driver. See
> > Documentation/sound/alsa-configuration.rst.
> > You can try the bit 16 at first, for example.
> > 
> 
> > 
> 
> > Takashi
> 
> 
> Thanks. I tried fiddling around with it for a bit but so far limited success. I wasn't sure about the arguments or counting order of quirk_flags (some tidbits show it as hex, others as an array of booleans (?)) so tried a few different things. I have no other USB audio devices so didn't see a need to specify vendor or product ID while testing. 
> 
> 
> # modprobe snd_usb_audio quirk_flags=0x10000
> # modprobe snd_usb_audio quirk_flags=0x1
> # modprobe snd_usb_audio quirk_flags=0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1
> 
> No success with any, so far. Is there a way to make the process more verbose? I can see from the lights on the DAC that the initialisation works differently if I mess with the different quirks but that's not visible in syslog or outcome.

This option is passed per card instance, as the driver may hold
multiple cards.  Check your /proc/asound/cards.  The first argument of
quirk_flags is applied to the first USB-audio card, the second to the
second USB audio device, and so on.

At best, give alsa-info.sh output before and after applying the
quirk.  Run the script with --no-upload option and attach the
outputs.

And, as a reference, you can see the existing quirk tables in
sound/usb/quirks.c.


Takashi