[wdmaudiodev] Re: Linux UAC2 gadget

  • From: "Jerry Evans" <jerry@xxxxxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Thu, 5 Dec 2019 10:48:40 -0000

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://www.freelists.org/post/wdmaudiodev/Raspberry-Pi-OTG-Audio>  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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