On Fri, May 21, 2021 at 3:50 PM Georges Basile Stavracas Neto <georges.stavracas@xxxxxxxxx> 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 > >
