hid descriptor request lost

[maor1993]

Hey, I've been trying to implement an HID demo. used an hid example from lufa as the descriptor values and cross compared the code they we're using with your implantation.

I will note that CDC loopback works well, so does modding it to become a debug print path.

I'm running on the stm32f042 nucleo.

long story short: The computer gets the device descriptor, but gets no reply from HID Report request.

looking at wireshark the computer sends it as GET DESCRIPTOR HID REPORT (0x22)

but when I place a breakpoint on the point where it should receive it, nothing gets through, meaning the callback is not triggered.

here is a link to the repo: https://github.com/maor1993/StamDevPlayGround/blob/master/stam/Src/usbhid.c

Any tests I should do to find out why? Thanks, Maor.

[dmitrystu]

Well, it happens because it's an request to the interface, not to the device. It can be handled in your hid_control subroutine. So, it this implementation of the usbd core get_descriptor callback works only with requests to the device. Looks like a bug, and code must be revised.

[dmitrystu]

There is no standard GET_DESCRIPTOR request on interface level. It can be added to the core but i'm afraid of the side-effects.

[maor1993]

Would it be possible to add a callback for interface requests as well? it seems this is the only way to support HID devices.

[microwavesafe]

I use this in the callback for HID devices

usbd_respond
usbd__control(usbd_device *dev, usbd_ctlreq *req, usbd_rqc_callback *callback)
{
    // class request
    if (((USB_REQ_RECIPIENT | USB_REQ_TYPE) & req->bmRequestType) == (USB_REQ_INTERFACE | USB_REQ_CLASS)) {
        switch (req->bRequest) {
            case USB_HID_SETPROTOCOL:
                usbd_hid__.protocol = (uint8_t)(req->wValue);
                return usbd_ack;

            case USB_HID_GETPROTOCOL:
                dev->status.data_ptr = (uint8_t*)&usbd_hid__.protocol;
                dev->status.data_count = sizeof(usbd_hid__.protocol);
                return usbd_ack;

            case USB_HID_SETIDLE:
                usbd_hid__.idle = (uint8_t)(req->wValue >> 8);
                return usbd_ack;

            case USB_HID_GETIDLE:
                dev->status.data_ptr = (uint8_t*)&usbd_hid__.idle;
                dev->status.data_count = sizeof(usbd_hid__.idle);
                return usbd_ack;

            default:
                return usbd_fail;
        }
    }
    // standard request
    else if (((USB_REQ_RECIPIENT | USB_REQ_TYPE) & req->bmRequestType) == (USB_REQ_INTERFACE | USB_REQ_STANDARD)) {
        switch (req->wValue >> 8) {
            case USB_DTYPE_HID_REPORT:
               dev->status.data_ptr = (uint8_t*)usb_hid_report_descriptor;
               dev->status.data_count = sizeof(usb_hid_report_descriptor);
               return usbd_ack;;

         default:
             return usbd_fail;
        }
    }

    return usbd_fail;
}

[maor1993]

Hey, @microwavesafe works perfect. @dmitrystu , I suggest you add an HID example, perhaps using what microwavesafe did.

closing this issue.