brickhid creates Bluetooth L2CAP sockets and accepts connections on PSMs 17 and 19 which are allocated to HIDP.īrickhid does not implement the full HID specification. The following procedure can be used to check whether this situation changes in future zcat /proc/config.gz | grep 'HIDP\|HIDRAW'Īs a consequence, brickhid must interface with the Bluetooth stack at a lower layer, namely L2CAP. Unfortunately the Linux kernel in the stock EV3 firmware has been compiled without support for HIDP and HIDRAW, Which allows applications to access more exotic HID devices such as game controllers. The Linux kernel also has an interface called HIDRAW HIDP is supported on most Linux distributions, which is why Bluetooth keyboards and mice usually work out-of-the-box. For keyboards, mice and gamepads, the relevant profile is called HIDP The Bluetooth standard specifies 'profiles', which are essentially dedicated protocols for various types of devices.
The EV3 brick contains a generic Bluetooth transceiverĪnd the firmware includes Bluez, the standard Linux Bluetooth protocol stack.
