Combined HID Descriptor Mouse and Keyboard doesn't work

[duesentrieb]

Hello everyone,

I'm currently trying to emulate both a keyboard and the mouse as hid-devices using stm32 and the descriptor that contains two collections.

The descriptor:

// Keyboard
0x05, 0x01,                   
0x09, 0x06,                    // USAGE (Keyboard)
0xa1, 0x01,                    // COLLECTION (Application)
0x85, 0x01,					   // report id 1
0x05, 0x07,                    //   USAGE_PAGE (Keyboard)
0x19, 0xe0,                    //   USAGE_MINIMUM (Keyboard LeftControl)
0x29, 0xe7,                    //   USAGE_MAXIMUM (Keyboard Right GUI)
0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
0x25, 0x01,                    //   LOGICAL_MAXIMUM (1)
0x75, 0x01,                    //   REPORT_SIZE (1)
0x95, 0x08,                    //   REPORT_COUNT (8)
0x81, 0x02,                    //   INPUT (Data,Var,Abs)
0x95, 0x01,                    //   REPORT_COUNT (1)
0x75, 0x08,                    //   REPORT_SIZE (8)
0x81, 0x03,                    //   INPUT (Cnst,Var,Abs)
0x95, 0x05,                    //   REPORT_COUNT (5)
0x75, 0x01,                    //   REPORT_SIZE (1)
0x05, 0x08,                    //   USAGE_PAGE (LEDs)
0x19, 0x01,                    //   USAGE_MINIMUM (Num Lock)
0x29, 0x05,                    //   USAGE_MAXIMUM (Kana)
0x91, 0x02,                    //   OUTPUT (Data,Var,Abs)
0x95, 0x01,                    //   REPORT_COUNT (1)
0x75, 0x03,                    //   REPORT_SIZE (3)
0x91, 0x03,                    //   OUTPUT (Cnst,Var,Abs)
0x95, 0x06,                    //   REPORT_COUNT (6)
0x75, 0x08,                    //   REPORT_SIZE (8)
0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
0x25, 0x65,                    //   LOGICAL_MAXIMUM (101)
0x05, 0x07,                    //   USAGE_PAGE (Keyboard)
0x19, 0x00,                    //   USAGE_MINIMUM (Reserved (no event indicated))
0x29, 0x65,                    //   USAGE_MAXIMUM (Keyboard Application)
0x81, 0x00,                    //   INPUT (Data,Ary,Abs)
0xc0,                           // END_COLLECTION
// Mouse
0x05, 0x01,        // USAGE_PAGE (Generic Desktop)
0x09, 0x02,        // USAGE (Mouse)
0xA1, 0x01,        // COLLECTION (Application)
0x85, 0x02,        //   REPORT_ID (2)
0x09, 0x01,        //   USAGE (Pointer)
0xA1, 0x00,        //   COLLECTION (Physical)
0x05, 0x09,        //     USAGE_PAGE (Button)
0x19, 0x01,        //     USAGE_MINIMUM (Button 1)
0x29, 0x03,        //     USAGE_MAXIMUM (Button 3)
0x15, 0x00,        //     LOGICAL_MINIMUM (0)
0x25, 0x01,        //     LOGICAL_MAXIMUM (1)
0x95, 0x03,        //     REPORT_COUNT (3)
0x75, 0x01,        //     REPORT_SIZE (1)
0x81, 0x02,        //     INPUT (Data,Var,Abs)
0x95, 0x01,        //     REPORT_COUNT (1)
0x75, 0x05,        //     REPORT_SIZE (5)
0x81, 0x03,        //     INPUT (Cnst,Var,Abs)
0x05, 0x01,        //     USAGE_PAGE (Generic Desktop)
0x09, 0x30,        //     USAGE (X)
0x09, 0x31,        //     USAGE (Y)
0x15, 0x81,        //     LOGICAL_MINIMUM (-127)
0x25, 0x7F,        //     LOGICAL_MAXIMUM (127)
0x75, 0x08,        //     REPORT_SIZE (8)
0x95, 0x02,        //     REPORT_COUNT (2)
0x81, 0x06,        //     INPUT (Data,Var,Rel)
0xC0,              //   END_COLLECTION
0xC0               // END_COLLECTION

 Using only the keyboard or mouse-part of the descriptor, everything works. But if the descriptor is applied as above, neither the mouse or the keyboard emulation are working. I'm using the custom hid class generated by STM32CubeIDE. When debugging the USBD_CUSTOM_HID_SendReport function, pdev->dev_state equals USBD_STATE_CONFIGURED if only keyboard or mouse descriptor applied, or USBD_STATE_SUSPENDED if the combined one from above is applied. Also, the operating system (Windows 11) accepts and configures the devices properly, no issues with the descriptor reported. Maybe someone experienced the same issue and can help me out?

Best regards

[Pavel A.]

Many STM32s have two host controllers. If there's one unused host controller, why not to utilize it? The hardware cost of this can be not higher than a hub chip. 

[Robmar]

Because this is a commercial project, and we don't add extra hardware to complicate the client's operation and increase manufacture costs, that's why.