[alsa-devel] [PATCH] ALSA: usb: Add support for Zoom R16/24 capture and midi interfaces

[Panu Matilainen]

On 11/29/2014 09:39 PM, Takashi Iwai wrote:
> At Sat, 29 Nov 2014 21:35:04 +0200,
> Panu Matilainen wrote:
>>
>> This makes the midi interface and capture work out of the box with
>> R16 (and presumably R24 too but untested). Playback stream would also
>> seem to function fine except for one caveat: no sound is produced,
>> so it is disabled for now.
>
> Could you give more comments in the playback iface why it's disabled?
> Ditto for ifnum=0.

Sure, I'll post an updated patch with added comments.

In the meanwhile I started looking at the mixer - this is just guessing 
but maybe its starting with outputs muted which could explain the 
playback stream running but without sound.

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?

FWIW there are other unrecognized descriptors too but those are 
associated with the other interfaces, which I guess I can ignore for now...

	- Panu -