[wdmaudiodev] Re: Linux UAC2 gadget

  • From: Robert Bielik <Robert.Bielik@xxxxxxxxx>
  • To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Thu, 5 Dec 2019 11:55:10 +0000

Hi Jerry,

Has this been channeled back into the linux kernel ?

Regards
/R

-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx <wdmaudiodev-
bounce@xxxxxxxxxxxxx> On Behalf Of Jerry Evans
Sent: den 5 december 2019 11:49
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Linux UAC2 gadget

Hi Chris



I got this working a few months back. The trick was to change the isoch
endpoints from ASYNC to SYNC as in



                .bmAttributes = USB_ENDPOINT_XFER_ISOC |
USB_ENDPOINT_SYNC_SYNC,



For reasons I no longer recall I also did this:



                //.bFunctionSubClass = UAC2_FUNCTION_SUBCLASS_UNDEFINED,

                .bFunctionSubClass = UAC2_FUNCTION_DESKTOP_SPEAKER,



The resulting gadget, running on an ARM64 board, interacted with Windows
correctly.



HTH



Jerry.



From: wdmaudiodev-bounce@xxxxxxxxxxxxx <wdmaudiodev-
bounce@xxxxxxxxxxxxx> On Behalf Of Chris Fryer
Sent: 05 December 2019 07:43
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Linux UAC2 gadget



Hi all,
Following on from this thread from Feb '18
<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fww
w.freelists.org%2Fpost%2Fwdmaudiodev%2FRaspberry-Pi-OTG-
Audio&data=02%7C01%7Crobert.bielik%40dirac.com%7Cea80e39e41c945f1e
72508d77970c6a9%7C266f25c575d44d978f448d816a1f6a35%7C1%7C1%7C637
111397600052766&sdata=xgtlUndXCL5SjnTBzV4pgLUyMWe%2B2bwJ5v04wR
R2uyI%3D&reserved=0>  I'm trying to get the linux usb 2.0 audio gadget
working on Windows 10.

I've added a feedback endpoint but the driver is still failing during load 
with:
[USBAudio2]FilterGraph::CreateSubDevice: port->Init() failed
0xc000028c(STATUS_RANGE_NOT_FOUND)

Full tracefmt output attached here.

I notice there's a comment that:
[USBAudio2]AudioFunction::ParseAcInterruptEndpoint: No AC Interrupt
endpoint present

Is that a requirement? Any pointers greatly appreciated.

Regards
Chris

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