Fix "Unknown protocol 0x0a in devcon notif" errors when trying to list
or pair new devices connected to the Nano receiver with device ID c534.
This receiver is limited to 2 devices only and does not allow unpairing.
Update the hidraw autodetection since the first detected hidraw device
is wrong. Check the interface number, similar to Solaar, this avoids
more complicated HID descriptor parsing.
To confirm whether a device supports the HID++ protocol, either use
`sudo lsusb -v046d:` (without a kernel driver bound to it) or use
hidrd-convert -o spec /sys/class/hidraw/hidrawX/device/report_descriptor output.txt
to find a Vendor-Specific page.
- Add second official Unifying receiver (mentioned in from hid-logitech-dj.c)
and "Unifying Ready" Nano receiver (mentioned in Solaar).
- Introduce an extra label for easier extension.
- Remove world-writable suggestion, no reason to do so with uaccess.
