Re: [Libusb-devel] Receiving interrupt transfer packets

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

On Tue, 20 Jul 2010, Nikolai Kondrashov wrote:

> I want to simply dump whatever a device transmits via its HID interface
> interrupt IN endpoints when it is operated in different ways (all of them,
> preferably).

Those "operations" being carried out by your tool set, right?

> My idea (possibly naive and insufficiently verified) is that a lot of input
> devices not working with Linux could be made to work by fixing their report
> descriptors. Not really fixing, but just feeding the generic HID driver with
> a fixed one.

This is already done in some cases.  I don't know to what extent it is 
true for other input devices that don't work with Linux; my guess is 
that more often the problem is lack of a proper driver rather than 
errors in the descriptors.

Regardless, you should discuss this with the maintainer of the usbhid 
subsystem: Jiri Kosina <jk...@su...>, mailing list 
<lin...@vg...>.  He knows more about it than anybody else.

> For that I need to get the report descriptors and reports themselves.

It's possible to obtain the report descriptors by running "lsusb -v".  
So you must be concerned with how to obtain the reports.

> I can't own or rent all such devices, so I plan to ask their owners to
> collect diagnostics for me, plus maybe get some shop assistants to give me 5
> minutes with them to collect it myself.
> 
> The diagnostics tool set is just a console "wizard" asking the user to do
> some input and recording whatever was produced when it was done. I have most
> of it implemented for graphic tablets, but it dumps evdev events instead
> currently.
> 
> > Would you be satisfied simply to have an option in libusb for printing out
> > a record of all the data getting sent or received?
> Thank you :) Well, it would do if nothing else works, of course. But I think
> the tool would be better.

How do you envision the tool working?

Alan Stern