[libhid-discuss] Multiple duplicate interfaces?

[Charles Lepple]

On Oct 2, 2010, at 3:47 PM, Frank Rizzo wrote:

>> Your best bet is to try the operating system interfaces first.  
>> Since  you posted output from 'lsusb', I'm going to assume Linux.
>
> Yes, Linux.  Sorry for that omission.
>
>> If you scan a barcode, does it look like characters are being typed  
>> in your terminal?
>
> Yes!  And I want to detach it from the OS, and have it talk only to  
> my app, so as to not screw up the other stuff going on.

If you detach it from the OS, you will have to handle all of the HID  
keyboard transactions. libhid doesn't do any of that for you.

>> Not sure what you mean by "multiple duplicate interfaces", since  
>> there seems to only be one configuration listed in lsusb (and one  
>> interface  for that configuration). If you are referring to the  
>> duplicate debug  lines from libhid, that's a well-known bug in the  
>> hidparser debug code  relating to ranges of Usage codes (from  
>> "Usage Minimum" and "Usage  Maximum" tags in the HID report  
>> descriptor).
>
>
> I read a few months back in the archives, and saw a discussion about  
> this, and about how the 2nd DWORD being 0 was a bug, but never saw a  
> conclusion to it.
>
> So, on this line:
>
> path: 0x00010006.0x00000000; type: 0x80
>
> the 0x00010006 is correct, but the 0x00000000 is incorrect, is that  
> right? If it IS, how do I get the correct 2nd half of the path?

Right. There is a comment about 3/4th of the way through http://svn.debian.org/wsvn/libhid/trunk/test/test_libhid.c 
  that explains how to find the path from lsusb output.