[wdmaudiodev] Re: USB Audio Driver/Device problems

  • From: Tim Roberts <timr@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Fri, 06 Nov 2009 10:08:47 -0800

Steve Hayashi wrote:
> I downloaded a USB analyzer to see what might be going on that causes
> intermittent functionality.  From the looks of things, the host
> queries the device and attempts to get some member variables, like
> mute functionality, volume control, treble, bass, etc.  The host then
> sends a select_interface packet, sets the volume controls, and then
> we're all good.
> Unfortunately, my device will send a stall response to the member
> variable query (I don't know why), and the host driver clearly does
> not like this, and it spirals out to the host just sending generic
> queries (and the device responding back).

Is it always the same request?  If your descriptors say that you support
volume, then it is a protocol violation for you to stall a volume
request.  Windows 7 is a lot pickier than XP was about following the

> I don't want to send a log file out to the entire mailing list, but I
> can send it out to anyone interested in taking a look at it (they're
> html files).  Overall, the interaction seems a little strange to me,
> but I'm chalking it up to lack of full USB knowledge.

You can send it by email and I'll see if it looks funny.

Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.


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