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

[Charles L. <cl...@gm...>]

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.

--=20
- Charles Lepple