[wdmaudiodev] Re: USBAudio Driver Fails to Start In Vista
- From: Tim Roberts <timr@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Fri, 24 Mar 2006 14:23:59 -0800
Sam Tertzakian wrote:
> Hi, Hakon,
>
>
>
> Yes, it must be a USB 1.1 Audio on a USB 2.0 Bus.
>
Let's be very precise: we're talking about a USB 2.0 device, on a USB
2.0 bus, running USB Audio Class 1.0, at the speed of USB 1.1. Right?
There is no "USB 1.1 Audio".
> When I load it in XP it says, "USB Audio" in device manager and for
> location it says "Location 0 (USB 2.0 Video)".
>
Video? Really?
> So are you saying that the firmware needs to be changed even thought
> it works fine under XP (to specify an interval of 8 for the interface
> so it uses the same 1ms data distribution of an USB 1.1 device)?
>
The EHCI driver will support iso pipes at high speed. USBAUDIO.SYS,
which is specific to audio class, apparently will not. To support more
than one packet per frame, the requests have to be submitted in
multiples of 8. As I recall, USBAUDIO.SYS submits 10 packets per
request. That doesn't work.
> Is it possible to write a Filter Driver to correct this problem?
>
I don't think so. Although many descriptor problems can be fixed, in
this case you'd have to rewrite the device descriptor before it went in
to EHCI. Is the firmware really that hard to change?
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
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