[libhid-discuss] HID Usage path

[Jorgen Lundman]

This is probably a common question by now :)  I think it would help if 
you provided the output of hid_dump_tree() in test_hid.c, since "lsusb" 
is a Linux only command. (right?)

Anyway, when dumping the device I am interested in, I get:

device identification of HIDInterface 005/007-6993-b001-00-00[0]:
   dev_handle:    0x00302c00
   device:        0x01808a00
   location:      005/007-6993-b001-00-00
   manufacturer:  Yealink Network Technology Ltd.
   product:       VOIP USB Phone
parse tree of HIDInterface 005/007-6993-b001-00-00[0]:
   path: 0x000b0001.0x00000000; type: 0x80
   path: 0x000b0001.0x00000000; type: 0x80
   path: 0x000b0001.0x00000000; type: 0x80

[big cut]

   path: 0x000b0001.0x00000000; type: 0x80
   path: 0x000b0001.0x00000000; type: 0x80
   path: 0x000b0001.0x00000000; type: 0x90
   path: 0x000b0001.0x00000000; type: 0x90
   path: 0x000b0001.0x00000000; type: 0x90
   path: 0x000b0001.0x00000000; type: 0x90
   path: 0x000b0001.0x00000000; type: 0x90
   path: 0x000b0001.0x00000000; type: 0x90
   path: 0x000b0001.0x00000000; type: 0x90

[cut]


Now, test_hid.c seems to imply it should be of length 3, not 2. But 
someone else on this list showed using just 2. Another email said to 
ignore those ending with 0000's. Except all my 0x80 and 0x90 end in 0000's.

Am I right to use:

#define PATHLEN 2
   int const PATH_IN[PATHLEN] = { 0x000b0001, 0x00000000 };
   int const PATH_OUT[PATHLEN] = { 0x000b0001, 0x00000000 };

Sending the 6 test bytes at least say:

   TRACE: hid_set_output_report(): sending report ID 0x00 (length: 6) to 
USB device 005/007-6993-b001-00-00[0]...
  NOTICE: hid_set_output_report(): successfully sent report to USB 
device 005/007-6993-b001-00-00[0].



Finally, is this something static and specific to a device? Can I safely 
embed this value in my sources, or am I supposed to scan for it each 
time as it is dynamic?

Good news is that libhid appears to run rather well on OsX. Even though 
I do get some warnings about untested code. That it manages to claim the 
device is much further than I got with libusb.

Lund

-- 
Jorgen Lundman       | <lundman at lundman.net>
Unix Administrator   | +81 (0)3 -5456-2687 ext 1017 (work)
Shibuya-ku, Tokyo    | +81 (0)90-5578-8500          (cell)
Japan                | +81 (0)3 -3375-1767          (home)