[wdmaudiodev] Re: USB audio descriptor question

  • From: Uwe Kirst <u.kirst@xxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Mon, 18 Feb 2008 11:36:21 +0100

Tim Roberts schrieb:
Uwe Kirst wrote:
Hello,
I want to develop an USB audio device and I'm new with this stuff. So far I did only PCI and Firewire devices. My question is about the descriptors: It seems to be possible that a devices is detected and Windows shows up the vendor and product information without loading a driver or looking at a special .inf file.
No, this is all driven by the device class in the device descriptor. Microsoft has drivers for most of the standard USB device classes (HID, Audio, Video, Printer, Scanner, Storage, etc.). A USB storage device has the storage device class in its device descriptor. Windows will first search for a specific match based on VID, PID, and Revision; then it looks for VID and PID; then it looks for device class.

Thank you for your response.
I would like to see my device detected as "Found new Hardware: My special custom USB audio Device" instead of just "USB device". There may be something wrong with my string descriptors. I found out so far that there has to be a terminating NULL at the end of every string otherwise the USB compliance test crashes. The test shows at least the product string and the language if I add the termination NULL.
The usbview DDK example on the other hand does not show any of my strings.
/Uwe

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