Bluetooth keyboard

This article describes how to set up a Bluetooth HID keyboard with Arch Linux, bluez version 5.

Pairing process

This article or section is a candidate for merging with Bluetooth.

Notes: Pairing process, and some troubleshooting related to it, are redundant with general device setup on Bluetooth page, and should be merged there. Keyboard-specific info would stay on this page. (Discuss in Talk:Bluetooth#Merging general setup from Keyboard, Mouse, Headset pages)

Login to the affected computer by a wired keyboard or by ssh.

First, make sure the local Bluetooth controller (e.g. a Bluetooth dongle the built in Bluetooth radio) is recognized:

# lsusb

Bus 001 Device 004: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp. LAN9500 Ethernet 10/100 Adapter / SMSC9512/9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The above output is from a Raspberry-Pi revision 'B' with archlinux-arm and a Keysonic Bluetooth Dongle.

Three items worth remembering:

Bluetooth devices (keyboard) and controllers (dongle) need to be paired once.
The Bluetooth controller needs to be powered up after every boot.
The Bluetooth controller needs to be told to connect to the keyboard after every boot.

Pairing is a one time process, required only once. There are Bluetooth keyboards sold with a Bluetooth dongle which come already paired, but that is not certain. We will use the bluetoothctl command from bluez-utils to pair our dongle and the keyboard.

Power up can be done with bluetoothctl, or automatically in /etc/bluetooth/main.conf, see below.

Same for connecting, either bluetoothctl or hcitool can be used, the latter is more useful for scripting.

We will use bluetoothctl for the pairing process. Run the command to get at the [bluetooth]# prompt.

# bluetoothctl

[bluetooth]#

Note: If you are on a color console: the word "bluetooth" is in the default color as long as no devices are available, and blue as soon as required devices and/or controllers have been found.

While in bluetoothctl power up the controller:

[bluetooth]# power on

Changing power on succeeded
[CHG] Controller 06:05:04:03:02:01 Powered: yes

Next, tell bluetoothctl to look only for keyboards, and make that the default agent:

[bluetooth]# agent KeyboardOnly

Agent registered

[bluetooth]# default-agent

Default agent request successful

Next, put your controller (the local dongle) in pairable mode:

[bluetooth]# pairable on

Changing pairable on succeeded

Next, put your keyboard in an active mode, where it is discoverable, i.e. pairable. Some keyboards have a special button for this on the underside, or require a special key combination to be pressed. See the documentation of your keyboard. Please note that this discoverability of a device is time limited; some devices are only visible for 30 seconds, other for 2 minutes. Your mileage may vary.

Next, let the controller scan the Bluetooth frequencies for a suitable device:

[bluetooth]# scan on

Discovery started
[CHG] Controller 06:05:04:03:02:01 Discovering: yes

After a few seconds the address of the keyboard should be listed as found. This line will repeat over and over, but will not stop you from entering new commands.

Next, actually do the pairing. The address used is the Bluetooth MAC address of the keyboard:

[bluetooth]# pair 01:02:03:04:05:06

Pairing successful

Note: Some keyboards, such as Microsoft Surface Ergonomic, will send a pass code (e.g. [agent] Passkey: 501334) which has to be typed in on the Bluetooth keyboard followed by the key Enter in order to pair successfully. Use paired-devices command to double check if the pairing succeeded.

Next, make this a trusted device (this allows the device to establish the connection on itself). Again, the Bluetooth MAC address is the address of the keyboard device:

[bluetooth]# trust 01:02:03:04:05:06

Trusted

Next and finally connect to the device (keyboard). Again, the Bluetooth MAC address is the address of the keyboard device:

[bluetooth]# connect 01:02:03:04:05:06

Connection successful

Done. Leave the bluetoothctl utility:

[bluetooth]# quit

Now the external device (i.e. keyboard) and the USB Bluetooth dongle are paired permanently, unless you break the pairing intentionally.

Troubleshooting

Bluetooth controller does not show up in lsusb

Manually load the generic Bluetooth driver:

# modprobe btusb

For integrated Bluetooth controller, some are not internally wired through USB, and only appear using lspci.

Bluetooth controller is not visible in bluetoothctl

Check the unit status of bluetooth.service.

If the [bluetooth]# prompt is blue and you get No default controller available message when powering on the controller with power on, run bluetoothctl as root.

Bluetooth keyboard does not work

Start with basic troubleshooting steps : does the device have power; if so, did it connect to the Bluetooth controller? If not, try with another controller or your smartphone to confirm where the issue lies.

Error: hci0 ACL packet for unknown connection handle 4

Try a reset with hciconfig hci0 reset

Alt and Super are swapped

Some keyboards have separate macOS and Windows mode. When the keyboard is connected or when modes change, the Apple mode may activate. Remove the hid_apple kernel module and re-connect the keyboard:

# rmmod hid_apple

If this works, blacklist the module to have a permanent solution.

Xorg

Device should be added as /dev/input/event* and your Xorg should add it automatically if you did not disable such feature.