Re: [Libusb-devel] WinUSB and SHORT_PACKET_TERMINATE setting

[Rich v. L. <rhv...@gm...>]

Thanks for confirming that, Alan.  I took your suggestion and it seems to be
working, BTW.

On Wed, Sep 21, 2011 at 10:30 AM, Alan Stern <st...@ro...>wrote:

> On Wed, 21 Sep 2011, Rich von Lehe wrote:
>
> > I saw a thread from an archive where a few WinUSB settings were debated.
>  I
> > *think* this is the right forum to ask this, but forgive me if it's not.
> >
> >
> http://libusb.6.n5.nabble.com/To-understand-the-behavior-of-WinUSB-backend-td510213.html
> >
> > In that thread it looked like it was decided to always set
> > SHORT_PACKET_TERMINATE to false (0).  I was just curious if this decision
> > was final or if there was any way I could enable that feature in WinUSB
> from
> > Libusb-1.0.  I disagree with the characterization that it is meant to
> > support bad or non-compliant devices.  In our case, the USB silicon
> simply
> > provides the segments of the payload as they arrive.  The firmware must
> see
> > a final segment that is less than a full 64-byte segment to determine
> > completion.  If the overall payload is a multiple of 64 bytes, we need
> the
> > zero-length packet to indicate completion.
>
> Currently libusb doesn't support this at all, although there's no
> reason it couldn't.  It shouldn't be done by setting a WinUSB option,
> though; it should be integrated directly into libusb for use on all
> operating systems.
>
> In the meantime, you can always accomplish the same effect by sending
> an explicit 0-length packet to your device at the end of each transfer
> whose total length is multiple of 64.
>
> Alan Stern
>
>