Re: Bug in usbser.sys?

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: Philip Lukidis (pagefault0x0_at_hotmail.com)
Date: 10/26/04 

Date: Tue, 26 Oct 2004 13:55:04 -0400

"Randy Aull (MSFT)" <randyau@microsoft.com> wrote in message
news:417d37d6$1@news.microsoft.com...
> This is actually expected behavior. From what you have said, I'm certain
> that your endpoint's MaxPacket is not greater than 64 bytes.
> USB IO will only complete in one of the following situations:
> 1. All of your requested data has been received (your buffer is full)
> 2. A short packet is received (any packet with fewer bytes than
MaxPacket)
> 3. An error occurs (stall condition on the endpoint)
> 4. The IO is cancelled
>
[snip]

Hi, I was just wondering if this holds true for all USB transfers types
(including isochronous transfers, regardless of which flags I select)?

I'd just like to run through a simple example in order to see that I
understand. For example, concerning isochronous input, if I send down an
I/O request with a buffer of size 10*wMaxPacketSize, and say on the USB the
5th packet sent by the device is half full, will my completion routine be
called, even though the buffer is not yet full?

If so, how I can perform a transfer with different packet sizes in one I/O
operation? Must the last packet be smaller than wMaxPacketSize?

thanks,

Philip Lukidis

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