Merge 2 working report descriptors?

[mrzephy]

I'm making a device with a LED matrix and a volume control potentiometer. For the volume i used USAGE volume up and volume down, because I couldn't figure out how to increase volume with the Volume USAGE (everything i tried always decreased the volume). If anyone knows how to do this with only the VOLUME usage, it will help too. But to my problem:

I have 2 working report descriptors, if I use only 1 of them, they work. But when I tried to combine them (just join them and update the USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH appropriately), Windows will say the device cannot start (error 10). I've seen this error come up whenever Windows won't accept the report descriptor for some reason. I am using the free VID and PID for generic HID devices (0x16c0 and 0x05df).

The descriptor for volume (working):

Code: Select all

    0x05, 0x0c,                    // USAGE_PAGE (Consumer Devices)
    0x09, 0x01,                    // USAGE (Consumer Control)
    0xa1, 0x01,                    // COLLECTION (Application)
    0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
    0x25, 0x01,                    //   LOGICAL_MAXIMUM (1)
    0x09, 0xe9,                    //   USAGE (Volume Up)
    0x09, 0xea,                    //   USAGE (Volume Down)
    0x75, 0x01,                    //   REPORT_SIZE (1)
    0x95, 0x02,                    //   REPORT_COUNT (2)
    0x81, 0x06,                    //   INPUT (Data,Var,Rel)
    0x09, 0xe2,                    //   USAGE (Mute)
    0x95, 0x01,                    //   REPORT_COUNT (1)
    0x81, 0x06,                    //   INPUT (Data,Var,Rel)
    0x95, 0x05,                    //   REPORT_COUNT (5)
    0x81, 0x07,                    //   INPUT (Cnst,Var,Rel)
    0xc0,                          // END_COLLECTION

The descriptor for display (working):

Code: Select all

    0x05, 0x14,                    // USAGE_PAGE (Alphnumeric Display)
    0x09, 0x01,                    // USAGE (Alphanumeric Display)
    0xa1, 0x02,                    // COLLECTION (Logical)
    0x09, 0x2c,                    //   USAGE (Display Data)
    0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
    0x25, 0x01,                    //   LOGICAL_MAXIMUM (1)
    0x75, 0x01,                    //   REPORT_SIZE (1)
    0x95, 0x80,                    //   REPORT_COUNT (128)
    0x91, 0x02,                    //   OUTPUT (Data,Var,Abs)
    0xc0,                          // END_COLLECTION

So my problem is joining these 2 working descriptors so I can use both features at the same time. Any help is appreciated!

Thanks,
Jan