[wdmaudiodev] Enumeration error of USB audio device

  • From: "Daire O'Neill" <oneill.daire@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Thu, 22 Sep 2011 02:59:22 -0700


I am developing a composite USB audio/MIDI device. It is Audio Class 2.0
compliant, so it works
without a driver on OS X (as Core Audio supports UAC 2.0), and I have
developed a custom audio driver for Windows.
However I still use usbaudio.sys for MIDI on Windows.

This works fine on Vista and Windows 7: when I connect the device, it loads
usbaudio.sys to the MIDI interface,
but does not load anything to the audio interface. I then install my custom
driver to the audio interface.

But when I connect the device to an XP machine, XP tries to load
usbaudio.sys to the audio interface as well, and then
crashes. The machine will freeze and I need to hold the power button to
force shut down the PC.

I checked the USB descriptors using the UVCView tool from the DDK, but it
does not show any errors. Oddly, if I increase the audio channel
count to a high number (16 in, 10 out) then XP will NOT load the
usbaudio.sys driver, as if it realizes it cannot support this number of
and gives up. But for my desired configuration of 4 channels in, 4 out, this
problem occurs.

Does anybody know how I can prevent usbaudio.sys from loading to my device?
Also, any tools or logs I can check to see the error status
of usbaudio.sys would be very helpful.

Many thanks,


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