Re: [Libusb-devel] claim interface fails when claimed by usbhid driver

[Brian N. <br...@tw...>]

Charles Lepple wrote:

>On 5/22/05, Brian Nelson <br...@tw...> wrote:
>  
>
>>The problem I'm having is the usb_claim_interface call fails because
>>it's already claimed by the usbhid driver.  I can disconnect it from the
>>driver and the code works fine, but that's not what I want to do,
>>because I want to maintain the joystick functionality that I already have.
>>    
>>
>
>Unfortunately, while the kernel provides a "detach driver" call, it
>does not offer a corresponding "reattach driver" call.
>
>There are a couple of hooks in the kernel HID driver to handle odd
>devices, but your situation might require a nontrivial patch.
>
>The other option is to "fly blind" and just issue your command without
>claiming the interface. The kernel should queue your control message
>such that it will not be mixed up with other control message/response
>pairs from the HID driver, but there are no guarantees with that
>method.
>
>  
>
By "flying blind," are you saying I should try just calling 
usb_control_msg without calling usb_claim_interface first?  I think I've 
done that, and usb_control_msg just returns an error.

If you're not talking about that (perhaps something outside of libusb?), 
can you give me a pointer in the right direction?

Thanks!
-Brian