Re: Motu M4 - where to report this issue?

[Geraldo Nascimento <geraldogabriel@gmail.com>]

On Fri, May 21, 2021 at 3:50 PM Georges Basile Stavracas Neto
<georges.stavracas@gmail.com> wrote:
>
> Greetings ALSA community,

Hey, Georges!

>
> I recently acquired a Motu M4 interface, and seems to be working
> well so far. Everyday usage is completely functional.
>
> However, I noticed an odd sound artifact that happens from time
> to time when using DAWs like Ardour and Waveform11. It's a windy,
> ghostly sound that happens whenever I open any DAWs (the simple
> act of opening them triggers this). Interestingly, audio apps that
> use PulseAudio do not suffer from this issue. It's hard to describe
> it, so I recorded a video reproducing this problem:
>
> https://youtu.be/bM8x-YuXLVI
>
> A few things I've discovered while trying to understand what's
> going on:
>
> * It only happens with apps that use JACK or ALSA APIs. Using
>   PulseAudio (through PipeWire) does not trigger it.

I assume you are using PipeWire for JACK support and using "pw-jack
ardour" for example to start Ardour.

Could you stop PipeWire with "systemctl --user stop pipewire.service
pipewire.socket pipewire-media-session.service pipewire-pulse.service
pipewire-pulse.socket" and try to reproduce your issue using the
aplay/arecord commands?

Does the dmesg show anything unusual? Perhaps you should enable the
kernel boot option "snd_usb_audio.dyndbg=+p"

>
> * Seems like this sound is not an artifact of the interface; it
>   appears that this odd sound is sent to the interface through
>   USB. (You can see this in the video.)
>
> * It's triggered per track; in the video, for example, the drums
>   and keyboard tracks are affected independetly.
>
> I was oriented in #alsa at Freenode that the output of 'alsa-info'
> might be helpful, so here it is:
>
> http://alsa-project.org/db/?f=62f686710cc6c9344a8986707bf3d09248c514d1
>
> (I'm running this on top of a 5.12.5 kernel, which should include
> this fix: https://bugzilla.kernel.org/show_bug.cgi?id=207023)
>
> I'd like to know where should I report this bug (kernel bugzilla?),
> and if there's any other information I can provide to help fixing
> it.

Bugzilla definitely is the way to go.

You may need to recompile your kernel with suggested patch changes
over and over again.

>
> With respect,
> Georges
>
>