Re: Problem with USB High Speed Hub

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On Mar 11, 8:09 pm, chris.aselt...@xxxxxxxxx wrote:
On Mar 11, 1:33 am, Sushma <sushma.ye...@xxxxxxxxx> wrote:

If it was the problem with hub, it should fail even in Win XP. There
is no problem with Win XP. The problem is only with Win Vista.

Nope, this is totally incorrect.  Just because you swap one portion of
the system with another, and this causes the problem to go away, does
*NOT* mean that the problem you swapped was causing the problem.

It's entirely possible that you indeed have a bad hub which totally
misbehaves with respect to the USB specification, and XP was willing/
able to ignore it.  Vista has been documented to require more strict
USB standards adherence as compared to previous OSes.

Thank You all for the information.

I totally agree with chris, that the problem could be with the hub. I
have dual boot so im using the same computer for testing. As chris
said, Vista has been following to more USB standards.

But one other thing i have in my mind is, that the VCP driver i
developed has read and write polling threads. The VCP driver has read
completion routine registered. So, when i un-plug the Flash Device
which is connected to hub, the completion callback routine executes
and fails with status 0xC0000001 (STATUS_UNSUCCESSFUL).

The test scenario is PC<-->High Speed Hub 1<-->High Speed Hub 2<--
USBSerial Device. The Flash device is connected to High Speed Hub 1.

So my question why does my completion routines gets called when flash
is un-plugged. I dont have much details of USB spec. Kindly, give me
some suggestions or information.

Thank You.

Regards,
Sushma
.