[wdmaudiodev] USB audio changes in Vista?
- From: "Jerry Trantow" <jtrantow@xxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Fri, 28 Sep 2007 13:33:58 -0500
First some background:
Years ago I wrote a lower filter driver for a USB audio device that extended
the capabilities of a Philips usb audio part. We extended the hardware by
adding a 24 bit ADC and this required some vendor specific commands to
change the capture rate from 32K, 44.1K, 48K.
First, in the lower filter driver (to USBAudio.sys) I spoof
URB_FUNCTION_GET_DESCRIPTOR_FROM_DEVICE to expose modified capture
interfaces of 8/16/24 bits, stereo/mono, 32K/44.1K/48K.
Then I intercept URB_FUNCTION_SELECT_INTERFACE to send commands
(32K,44.1,48K FS) to my custom hardware that changes the ADC clock. This
worked fine for the Win9x and NT platforms up to Vista.
However, In Vista I am only getting 44.1K, 16 bit mono captures and 44.1K,
16 bit stereo playback. I don't know why Vista is always requesting these
interfaces??? My USB descriptors worked fine for all the previous OS
(including Macs). I see the calls to
DispatchInternalControl(URB_FUNCTION_GET_DESCRIPTOR_FROM_DEVICE)
And
URB_FUNCTION_SELECT_INTERFACE (Capture, 16 bit mono)
My questions are:
1) Has anything changed in the way USBAudio.sys asks for USB
descriptors?
2) What's the current tool for looking at what interfaces are exposed
by a USB audio device?
3) Any other ideas on tracking down this problem?
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