[alsa-devel] Zoom R16/24 playback slient

[Ricard Wanderlof]

On Wed, 30 Sep 2015, Panu Matilainen wrote:

> >>>> At Sat, 29 Nov 2014 21:35:04 +0200,
> >>>> Panu Matilainen wrote:
> >>>>>
> >>> The descriptors for interface 0 are garbage but what is there would seem
> >>> to map to logical elements by subtype and terminaltype, after those the> > data doesn't seem to add up (eg number of input/output channels
> >>> missing/wrongly placed etc):
> >>>
> >>> ** UNRECOGNIZED:  0b 24 01 00 01 35 00 03 01 02 03
> >>>      -> Header?
> >>> ** UNRECOGNIZED:  0c 24 02 05 01 01 00 02 03 00 00 00
> >>>      -> USB streaming input terminal?
> >>> ** UNRECOGNIZED:  09 24 03 08 01 03 00 05 00
> >>>      -> Speaker output terminal?
> >>> ** UNRECOGNIZED:  0c 24 02 09 01 02 00 08 00 00 00 00
> >>>      -> Microphone input terminal?
> >>> ** UNRECOGNIZED:  09 24 03 0c 01 01 00 09 00
> >>>      -> USB streaming output terminal?
> >>>
> >>> Anything there that might ring a bell, or other ideas where to start
> >>> poking at this thing?
> >>
> >> Yeah, most of these look almost sane, so any off-by-one firmware
> >> issue?

I was looking at this, and comparing it to the corresponding output from 
my Edirol UA-5, which is a class-complient (in its standard mode) 2 in / 2 
out device. The descriptors look suspiciously similar on both devices, 
especially considering that the R16 has 8 channels of input instead of 2 
and a MIDI interface which the UA-5 lacks.

I'm not sure exactly which version of the USB audio standard they 
correspond to, looking at the specifications for versions 1 and 2 it 
didn't seem to make sense, but they do happen to correspond very much to 
the descriptions in the following document:

https://www.silabs.com/Support%20Documents/TechnicalDocs/AN295.pdf

The fact that lsusb doesn't recognize them I would think boils down to the 
fact that it simply doesn't know about USB audio; it appears that the ALSA 
USB driver can make sense of the information, which is why the resulting 
entry in the quirks table doesn't need a FIXED_ENDPOINT quirk.

/Ricard
-- 
Ricard Wolf Wanderlöf                           ricardw(at)axis.com
Axis Communications AB, Lund, Sweden            www.axis.com
Phone +46 46 272 2016                           Fax +46 46 13 61 30