Re: [Libusb-devel] Receiving interrupt transfer packets

[Alan S. <st...@ro...>]

On Tue, 20 Jul 2010, Nikolai Kondrashov wrote:

> On 07/20/2010 09:00 PM, Alan Stern wrote:
> > I get it.  Then the answer to your original question is easy: You don't
> > need to worry about parsing report descriptors, variable report
> > lengths, or anything else.  Simply transfer individual maxpacket-sized
> > buffers and dump whatever you get.  All reports (except possibly the
> > longest) will terminate with a short packet.  In any case, the hid-dump
> > program wouldn't need to parse the reports or determine their
> > boundaries.
> Thank you, this is an answer I've hoped for :)! However, I think I've tried
> something like this. I mean, simply providing a large buffer and hoping the
> transfer will terminate when the report is finished, and it didn't work.
> I guess I did something wrong then.

Don't use a _large_ buffer -- use a buffer that is the maxpacket size.

Of course, the problem is that you generally won't know when a report
is finished.  Fortunately it looks like you don't really care, so long 
as all the data can be dumped.

Alan Stern