Bluetooth

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This article describes the configuration and usage of Bluetooth controllers and devices.

Prerequisites

This article assumes that udev and USB have been previously configured.

Installation

Kernel

In most cases enabling RFCOMM, HIDP, HCI USB and/or HCI UART should be sufficient. The User-space I/O driver for HID input devices should be enabled for Bluetooth keyboards and mice.

KERNEL Enabling Bluetooth support
[*] Networking support --->
      <*>   Bluetooth subsystem support --->
              [*]   Bluetooth Classic (BR/EDR) features
              <*>     RFCOMM protocol support
              [ ]       RFCOMM TTY support
              < >     BNEP protocol support
              [ ]       Multicast filter support
              [ ]       Protocol filter support
              <*>     HIDP protocol support
              [*]     Bluetooth High Speed (HS) features
              [*]   Bluetooth Low Energy (LE) features
                    Bluetooth device drivers --->
                      <*> HCI USB driver
                      <*> HCI UART driver
      <*>   RF switch subsystem support --->
    Device Drivers --->
          HID support --->
            <*>   User-space I/O driver support for HID subsystem

USE flags

BlueZ is an implementation of the Bluetooth protocol stack for Linux, and it is provided by the net-wireless/bluez package.

Cannot load package information. Is the atom net-wireless/bluez correct?

Bluetooth support can be enabled system-wide by setting the USE variable to bluetooth:

FILE /etc/portage/make.conf
USE="bluetooth"

Emerge

The system needs to be updated if the USE variable was set to bluetooth:

root #emerge --ask --changed-use --deep @world

Install BlueZ:

root #emerge --ask --noreplace net-wireless/bluez

Configuration

Permissions

Permissions for Bluetooth devices will be handled automatically if the USE variable is set to acl, and ConsoleKit or systemd is being used.

Alternatively, adding a user to the plugdev group will allow that user to access Bluetooth devices:

root #gpasswd -a <user> plugdev

Services

OpenRC

Start bluetooth:

root #rc-service bluetooth start

Start bluetooth at boot:

root #rc-update add bluetooth default

systemd

Start bluetooth:

root #systemctl start bluetooth

Start bluetooth at boot:

root #systemctl enable bluetooth

Usage

Controller setup

Display controller information:

root #hciconfig -a
hci0:   Type: BR/EDR  Bus: USB
        BD Address: 00:02:72:2F:A9:33  ACL MTU: 1021:8  SCO MTU: 64:1
        UP RUNNING PSCAN 
        RX bytes:1166 acl:0 sco:0 events:43 errors:0
        TX bytes:960 acl:0 sco:0 commands:43 errors:0
        Features: 0xbf 0xfe 0xcf 0xfe 0xdb 0xff 0x7b 0x87
        Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
        Link policy: RSWITCH SNIFF 
        Link mode: SLAVE ACCEPT 
        Name: 'BlueZ 5.21'
        Class: 0x000104
        Service Classes: Unspecified
        Device Class: Computer, Desktop workstation
        HCI Version: 4.0 (0x6)  Revision: 0x1000
        LMP Version: 4.0 (0x6)  Subversion: 0x220e
        Manufacturer: Broadcom Corporation (15)

Where hci0 is the name of the controller, and UP (3rd line) indicates that the controller is enabled.

Enable the controller if hciconfig indicates (with DOWN) (3rd line) that the controller is disabled:

root #hciconfig hci0 up

When attempting to enable the controller, the following message may be displayed:

root #hciconfig hci0 up
Can't init device hci0: Operation not possible due to RF-kill

In this case, query the state of the Bluetooth radio transmitter with net-wireless/rfkill:

root #rfkill list bluetooth
0: hci0: Bluetooth
        Soft blocked: no
        Hard blocked: no
Note
If Bluetooth is blocked or disabled in the BIOS/UEFI, rfkill may incorrectly list the controller as Hard blocked: no.

Unblock the controller if rfkill indicates (with Soft blocked: yes) that the controller is blocked:

root #rfkill unblock bluetooth

If rfkill indicates (with Hard blocked: yes) that the controller is blocked, unblock the controller by physical switch or keyboard function key.

Bluetooth controllers can be enabled automatically by setting AutoEnable=true in /etc/bluetooth/main.conf:

FILE /etc/bluetooth/main.conf
[Policy]
AutoEnable=true

Device pairing

Bluetooth devices need to be paired with a Bluetooth controller before they can be used. This is done by entering a PIN (or other code) on both devices via an interaction agent. Certain devices such as headsets do not allow entering an arbitrary PIN. These devices use a static PIN, which is usually 0000, 1111, 1234 or 9999. There are also devices (e.g. Sony BD Remote Control) that do not require PIN entry, and attempting to enter a PIN when prompted will result in failure. Paring can be skipped with such devices.

This article only covers device pairing with bluetoothctl, which is a command-line interaction agent provided by the net-wireless/bluez package. If a graphical desktop environment is being used, device paring can be done with a graphical interaction agent. For KDE use kde-plasma/bluedevil, for GNOME use net-wireless/gnome-bluetooth, and for GTK+ use net-wireless/blueman.

Note
Previously paired devices will need to be paired again when upgrading from BlueZ 4.

Start bluetoothctl:

user $bluetoothctl

List the available controllers:

[bluetooth]#list

Display information about a controller:

[bluetooth]#show controller_mac_address

Set the default controller:

[bluetooth]#select controller_mac_address

Power on the controller:

[bluetooth]#power on

Enable the agent and set it as default:

[bluetooth]#agent on
[bluetooth]#default-agent

Set the controller as discoverable (temporarily for 3 minutes) and pairable:

[bluetooth]#discoverable on
[bluetooth]#pairable on

Scan for devices:

[bluetooth]#scan on

Put the device into pairing mode. This generally involves pressing a button or a combinations of buttons, usually for several seconds.

Discover the device MAC address:

[bluetooth]#devices

Pair with the device:

[bluetooth]#pair device_mac_address

Enter the PIN if prompted:

[agent]PIN code: ####

Allow the service authorization if requested:

[agent]Authorize service service_uuid (yes/no): yes

Trust the device:

[bluetooth]#trust device_mac_address

Connect to the device:

[bluetooth]#connect device_mac_address

Display information about the device:

[bluetooth]#info device_mac_address

The device is now paired:

[bluetooth]#quit

See also