Re: USB driver : isochronous transfer

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From: max (max_mont_at_yahoo.fr)
Date: 08/06/04 

Date: 5 Aug 2004 23:16:22 -0700

In fact, I have no error.
IssueIsochTransfer is successful.
But, when I start reading, the camera is not initialized so I don't
receive any data and the error array returned is error 5 but this is
normal.

I can get 1 or 2 xfers before the problem arrive.

Then, the mouse is blocked, the isochronous callback isn't called and
I'm blocked in my reading thread which calls IssueIsochTransfer.

It's strange phenomenum.

"David Liao \(MS\)" <davli@online.microsoft.com> wrote in message news:<OYFZb3yeEHA.140@TK2MSFTNGP12.phx.gbl>...
> Have you checked the handle return from IssueIsockTransfer is valid or not?
> David Liao
>
> "Seung Yi" <seungyi@codetelligence_NOSPAMMERS_.com> wrote in message
> news:%23APa3WweEHA.3792@TK2MSFTNGP09.phx.gbl...
> > max wrote:
> >
> >> Hi everybody,
> >>
> >> I'm developing an USB driver to get images from Webcam.
> >> I get data by isochronous pipe.
> >>
> >> I'm using microsoft sample "317434 - How To Stream Isochronous Data
> >> Over Universal Serial Bus".
> >>
> >> I try to use only one buffer but I lose a lot of data.
> >> So I use 2 buffers. But it doesn't work : I call IssueIsochTransfer
> >> twice and the callback function is called twice. Then, I call
> >> IssueIsochTransfer twice again. But, the callback isn't called. So I'm
> >> blocked on the WaitforsingleObject(semaphore).
> >>
> >> have you got an idea about my problem.
> >>
> >> Thanks in advance for your help.
> >
> > What kind of error are you getting when you say "it doesn't work" ?
> >
> > --
> > Seung Yi
> > Senior Engineer
> > Codetelligence, Inc.
> > Web : www.codetelligence.com