Xone43C: USB communication

[Geraldo Nascimento]

On Tue, Jun 8, 2021 at 3:44 AM Roman Muller <klangrausch at wolke7.net> wrote:
>
> Hello Geraldo, hello all,
>
> sorry for spamming the list with such minuscule details.

Hi Roman, don't worry, your message is on topic...

> Thank you for your message! I did not hear from other people yet,
> so it's probably safe to assume that no one else is already working on it.
> Adding a section to the quirks-table does not help, the vendor-specific
> interfaces still don't work. Obviously they need extra initialization.
>
> Next step: sniffing again while running Windows in the vm.
> The interesting stuff is going on here:
> https://drive.google.com/file/d/1IlkR4ey9Gwsdrrf6jfOwNUVDtGcl_93-
> (Full log: https://drive.google.com/file/d/1VmSGVk8V1saw7qdPfbOH2d4HmZTrlzxj)
>
> From this I see several URB control messages going back and forth, for example
> the host sending 80bbf0, and the device responding accordingly. A bit later,
> and after sending 44ac00 six times (hola!?!?) I get isodesc[0-7] cross-device
> link for input; and once more for output, and the device reports success. These
> appear to be my eight channels. So far, so good for a first basic overview of
> the structure, but the tricky part is figuring out what message is doing what.

Your Xone:43C doesn't seem so esoteric from the usbmon capture you gave.

Is your capture complete from a software standpoint? i.e. are you
starting Serato or Traktor on the VM while doing the usbmon capture?

80bbf0 is just the data fragment, you need to replicate the whole
Setup Data of the packet.

> Only the manufacturer knows it, I need experiment and guessing
> with a lot of time and luck.

You probably don't really need to know for now what these control
messages are. There's a good chance replicating them is enough.

> Is there a common agreement where in the source code such control
> messages should be put? Probably an extra file?

I think you should worry for now in getting your device to work. Then
you share the patch with the maintainers and they will help you write
the best code possible.

But sound/usb/quirks.c seems like a good place to get started.

All the best,
Geraldo Nascimento

>
> Best,
> Roman