Re: [libusb] Windows HID API Clarifications

[Xiaofan C. <xia...@gm...>]

On Sat, Jun 19, 2021 at 12:14 PM Tim Roberts <ti...@pr...> wrote:
>
> On 6/18/21 6:56 PM, Xiaofan Chen wrote:
>
> What will be the good approach to reconstruct the HID report descriptor?
>
> I spent some time with this, and I don't think it is possible.  There's just not
> enough information in the "parsed descriptors" to do that.
>
> MAYBE (I haven't proven this to myself) you could use the same hub backdoor
> that "usbview" uses, and fetch the report descriptor that way.
>

I have tested the ideas and it does not seem to work,
IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION
can not be used to get the HID Report Descriptors.
https://github.com/libusb/hidapi/issues/249#issuecomment-865844126

Ref: https://community.osr.com/discussion/287808/ioctl-usb-get-descriptor-from-node-connection
For a HID report descriptor, the Recipient bits of bmRequestType must
be set to Interface (1).
IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION sets bmRequestType to 0x80.

-- 
Xiaofan