[libhid-discuss] help deciphering HID descriptor

[Hans-Christoph Steiner]

On Nov 29, 2007, at 4:24 AM, Triple Entendre wrote:

> On Wednesday, 2007-11-28 23:19:49, Hans-Christoph Steiner hans-at- 
> eds.org |libhid-discuss/my default allow| wrote:
>>
>> On Nov 28, 2007, at 5:17 PM, Peter Stuge wrote:
>>
>>> Sorry I'm being a bit selective in my answers, but I really can't
>>> help at all with the usage stuff. :\
>>>
>>>
>>> On Wed, Nov 28, 2007 at 04:51:15PM -0500, Hans-Christoph Steiner
>>> wrote:
>>>> My life would be easier if I could find a GNU/Linux box that had a
>>>> 'lsusb -vvv' that gave me something other than:
>>>>
>>>> Report Description:
>>>>     ** UNAVAILABLE **
>>>
>>> This is because the kernel hid driver has claimed the interface.
>>> Force detach it or just unload the driver and you should get more
>>> output from lsusb.
>>
>>
>> Cool, thanks, that was the first tip I needed, now I got the lsusb -
>> vvv output.  It turns out I had to ssh into my machine, stop all the
>> services that might be using the USB HID devices (like dbus),  and
>> rmmod all of the USB related modules (usbhid, hid, evdev, etc.).
>> Then lsusb -vvv gave me the Report Descriptor.
>>
>> So now I have it, but this one seems to be quite complicated, and I
>> am still not following it.  I am trying to trigger any of the output
>> usages:
>
> are you trying to make it rumble? if so you might need to
> add this idVendor and idProduct to one of the force-feedback-related
> kernel source files and recompile, with the kernel option for
> force feedback turned on. For example, the cordless version of
> this device (id 0xc219) appears in hid-ff.c.
>
> And some additional steps I've forgotten. Explicitly load the FF  
> module?


You shouldn't need the driver just to send commands to the device,  
AFAIK.  I am actually using this on Mac OS X also.  I am using libhid  
to actually avoid using the drivers.  As far as I understand it, with  
libhid, I can just send the commands directly to the device, and it  
should rumble.  A friend has this working on Windows (not using  
libhid but the Windows DDK).  I think the drivers provide a separate  
API for Force Feedback.  On Mac OS X, the driver is needed to use the  
Immersion API, for example.

.hc

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