LinuxMusicians

One more try

Yes, there is hope. The reason why i did not get the scheduling bug was, because i compiled the kernel without preemption. Now that i compile it as low-latency kernel i also get the "scheduling while atomic" bug (but without a hardlock), so i can have a look whats happening. Btw, for the new Ultrali...

I will be on irc freenode, #linuxmusicians this evening from 20:00 CEST. Better and faster to sort out the problems there.

Then split the patchfile into separate files for each patch and test them incrementally.

The patchfile consists of 3 patches, each starting with the line containing the "diff".

The 3rd patch is the important one for the channel hopping, so start with that one.

@bluebell Try to boot with the option "nowatchdog".

So, the attached patch should fix the following: - startup problems with pulseaudio or jack in duplex mode - channel hopping/bit crushing due to x-runs or sync issues - channel hopping when changing buffersize on the fly with jack_bufsize Note: It can take up to about 10 seconds for sound to come ba...

The patches will only go into the kernel after i get verification from users of the Ultralite AVB that they solve the problem. I can only check with my 16A AVB which uses the same vendor/product ID as all the other AVB products. With the patches, everything runs smooth. Without the patches, channel ...

My bad, i added the proper line in the clock.c file and then forgot about it.
I'd say linux is to blame here because the descriptor for the isoc IN endpoint has the implicit feedback bit set and that's ignored by the driver.

Now that the clock patch of @puleglot is in kernel 5.7-rc3, the patch for the AVB units reduces to this: --- linux-5.7-rc3/sound/usb/pcm.c.orig 2020-05-01 17:52:23.410987252 +0200 +++ linux-5.7-rc3/sound/usb/pcm.c 2020-05-01 17:42:05.458101734 +0200 @@ -366,6 +366,10 @@ static int set_sync_ep_implic...

The patches are so trivial that anybody should find the right place and copy it over for their kernel. Regarding USB 2/3: For a device it doesn't matter, if it is USB2 or USB3. From my developer view the xhci controller is a hundrt times easier to program than an ehci, and theoretically, it has a ma...

You could try my patches (attached are the patched files for kernel 5.6.2). The necessary changes are enclosed with /* drumfix */, so it should be easy to apply them to other kernel versions. The files need to be copied into directory <kernel-source>/sound/usb and then the kernel built. Some notes: ...

Unfortunately you will have to recompile wine.

Change the two constants in <wine-src>/include/mmddk.h:

#define MAX_MIDIINDRV (16)
#define MAX_MIDIOUTDRV (16)

to whatever number of ports you want to use.

The important lines are the two that i marked with the "+" at the beginning. And they are not in any kernel.

The firmware that should work without any additional patches is this one:

http://cdn-data.motu.com/downloads/audi ... B16.update

The only thing you loose is the Touchconsole.

if i remember right some Boss/Roland devices need to receive some output urbs first before they start filling input urbs. This requires a patch to the usb audio driver. in your case: In the file <your-kernel-src>/sound/usb/endpoint.c, function snd_usb_start_endpoint: + if (ep->chip->usb_id != USB_ID...