Bluetooth

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Wikipedia

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 (CONFIG_BT_RFCOMM), HIDP (CONFIG_BT_HIDP), HCI USB (CONFIG_BT_HCIBTUSB) and/or HCI UART (CONFIG_BT_HCIUART) should be sufficient. The User-space I/O driver for HID input devices (CONFIG_UHID) should be enabled for Bluetooth keyboards and mice. CONFIG_INPUT_UINPUT is used also in some rare devices (^[1]).

KERNEL Enabling Bluetooth support

[*] Networking support --->
      <M>   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 --->
                      <M> HCI USB driver
                      <M> HCI UART driver
      <*>   RF switch subsystem support --->
Device Drivers --->
      Input device support  --->
            [*]   Miscellaneous devices  --->
                  [*]   User level driver support
      HID bus support --->
            <*>   User-space I/O driver support for HID subsystem

Important
Kernel may fail to initialize RFCOMM/BNEP being compiled as built-in. System log for bluetooth service in this case will mention the lack of RFCOMM/BNEP support. And this in turn for example may break HSP/HFP headset profile initialization. So if dmesg says nothing about RFCOMM, better recompile as a module.

Firmware

Most Bluetooth controllers need firmware to function. If the controller is supported by Linux, dmesg will usually indicate if firmware is needed. The sys-kernel/linux-firmware package should provide the needed firmware, although some devices may need firmware that available in other package or provided only from the manufacturer.

root #emerge --ask --noreplace sys-kernel/linux-firmware

USE flags

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

USE flags for net-wireless/bluez Bluetooth Tools and System Daemons for Linux

`+mesh`	Add support for Bluetooth Mesh control application and advertising bearer.
`+obex`	Enable OBEX transfer support
`+readline`	Enable support for libreadline, a GNU line-editing library that almost everyone wants
`+udev`	Enable virtual/udev integration (device discovery, power and storage device support, etc)
`btpclient`	Enable BTP client
`cups`	Add support for CUPS (Common Unix Printing System)
`debug`	Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
`deprecated`	Build deprecated plugins
`doc`	Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
`experimental`	Build experimental plugins
`extra-tools`	Install tools that upstream doesn't install on purpose by default. All this tools shouldn't be used. Then, please notify upstream about you still need them to let them know the situation.
`midi`	Enable MIDI support
`selinux`	!!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
`systemd`	Enable use of systemd-specific libraries and features like socket activation or session tracking
`test`	Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
`test-programs`	Install tools for testing of various Bluetooth functions

Data provided by the Gentoo Package Database · Last update: 2024-10-18 19:05 More information about USE flags

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 is handled automatically by D-Bus, and access is granted to all users by default.

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

Enabling battery reporting

Note
The experimental USE flag needs to be enabled in net-wireless/bluez.

Warning
Using bluez's experimental mode may prevent some bluetooth microphones from connecting automatically.^[2]

Bluez has a feature to report a devices battery level to upower. This feature is currently experimental and not stable. Enable experimental mode:

FILE /etc/bluetooth/main.conf

[General]

Experimental=true

Restart bluetooth to apply the configuration changes:

root #rc-service bluetooth restart

Now upower should know the battery level of every device which supports sending its own battery level.

Usage

Controller setup

If, after following the steps described in the "Installation" and "Configuration" sections above, Bluetooth doesn't appear to be working, or an attempt to enable the controller results in a message such as:

Can't init device hci0: Operation not possible due to RF-kill

query the state of the Bluetooth radio transmitter with rfkill(8):

root #rfkill list bluetooth

0: hci0: Bluetooth
        Soft blocked: no
        Hard blocked: no

rfkill is provided by >=sys-apps/util-linux-2.31. It can also be installed by the unmaintained net-wireless/rfkill package.

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

In some instances Bluetooth controllers may have been soft-blocked by power management tools in udev. Make sure state is set to 1 in the corresponding rule file, or remove the following line entirely:

FILE /etc/udev/rules.d/10-local-powersave.rules

SUBSYSTEM=="rfkill", ATTR{type}=="bluetooth", ATTR{state}="1"

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. Pairing 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: ####

In case the pin is not prompted but needed, this command may need to be added before pairing with the device (see this post):

[bluetooth]#agent NoInputNoOutput

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

hciconfig

Warning
hciconfig is deprecated, and bluetoothctl (described above) should be used instead. hciconfig and other utilities are only available if net-wireless/bluez is installed with the deprecated USE flag enabled.

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.

Open and initialize HCI device:

root #hciconfig -a <hci0> up

Close HCI device:

root #hciconfig -a <hci0> down

Reset HCI device:

root #hciconfig -a <hci0> reset

Reset statistic counters:

root #hciconfig -a <hci0> rstat

Enable Authentication:

root #hciconfig -a <hci0> auth

Disable Authentication:

root #hciconfig -a <hci0> noauth

Enable Encryption:

root #hciconfig -a <hci0> encrypt

Disable Encryption:

root #hciconfig -a <hci0> noencrypt

Enable Page and Inquiry scan:

root #hciconfig -a <hci0> piscan

Disable scan:

root #hciconfig -a <hci0> noscan

Enable Inquiry scan:

root #hciconfig -a <hci0> iscan

Enable Page scan:

root #hciconfig -a <hci0> pscan

Get/Set default packet type:

root #hciconfig -a <hci0> ptype [type]

Get/Set default link mode:

root #hciconfig -a <hci0> lm [mode]

Get/Set default link policy:

root #hciconfig -a <hci0> lp [policy]

Get/Set local name:

root #hciconfig -a <hci0> name [name]

Get/Set class of device:

root #hciconfig -a <hci0> class [class]

Get/Set voice setting:

root #hciconfig -a <hci0> voice [voice]

Get/Set inquiry access code:

root #hciconfig -a <hci0> iac [iac]

Get/Set inquiry transmit power level:

root #hciconfig -a <hci0> nqtpl [level]

Get/Set inquiry mode:

root #hciconfig -a <hci0> inqmode [mode]

Get/Set inquiry data:

root #hciconfig -a <hci0> inqdata [data]

Get/Set inquiry scan type:

root #hciconfig -a <hci0> inqtype [type]

Get/Set inquiry scan window and interval:

root #hciconfig -a <hci0> inqparms [win:int]

Get/Set page scan window and interval:

root #hciconfig -a <hci0> pageparms [win:int]

Get/Set page timeout:

root #hciconfig -a <hci0> ageto [to]

Get/Set AFH mode:

root #hciconfig -a <hci0> afhmode [mode]

Get/Set Simple Pairing Mode:

root #hciconfig -a <hci0> sspmode [mode]

Set ACL MTU and number of packets:

root #hciconfig -a <hci0> clmtu <mtu:pkt>

Set SCO MTU and number of packets:

root #hciconfig -a <hci0> scomtu <mtu:pkt>

Delete link key from the device:

root #hciconfig -a <hci0> delkey <bdaddr>

Get local OOB data:

root #hciconfig -a <hci0> oobdata

Display supported commands:

root #hciconfig -a <hci0> commands

Display device features:

root #hciconfig -a <hci0> features

Display version information:

root #hciconfig -a <hci0> version

Display revision information:

root #hciconfig -a <hci0> revision

Add a device to the blacklist:

root #hciconfig -a <hci0> block <bdaddr>

Remove a device from the blacklist:

root #hciconfig -a <hci0> unblock <bdaddr>

Set LE Random Address:

root #hciconfig -a <hci0> lerandaddr <bdaddr>

Enable LE advertising:

root #hciconfig -a <hci0> leadv [type]

Show all commands device has support for:

root #hciconfig get commands

Disable Bluetooth

To disable Bluetooth at runtime, run the following command:

root #rfkill block bluetooth

To disable Bluetooth automatically on every boot, choose one of the following options:

Using udev to disable Bluetooth

When using UDEV, just install the following rule which will disable Bluetooth:

FILE /etc/udev/rules.d/80-disable-bluetooth.rules

SUBSYSTEM=="rfkill", ATTR{type}=="bluetooth", ATTR{state}="0"

Using OpenRC to disable Bluetooth

When using sys-apps/openrc, install the following script for local service and ensure it is executable:

FILE /etc/local.d/disable-bluetooth.start

#!/bin/sh
rfkill block bluetooth

root #chmod o+x /etc/local.d/disable-bluetooth.start

Disable Bluetooth at kernel level

When the kernel has modular Bluetooth support, disable loading of Bluetooth modules:

FILE /etc/modprobe.d/blacklist-bluetooth.conf

blacklist bnep
blacklist bluetooth
blacklist btusb

Utilities

The bluez-tools package provides a number of utilities, including bt-obex(1), for Bluetooth file transfers, and bt-network(1), a Bluetooth network manager.

Troubleshooting

TLP and laptop_mode

If laptop-mode-tools is installed or TLP make sure they're not disabling Bluetooth to save power.

XBOX ONE controller pairing

It's a known issue that XBOX ONE wireless controllers will refuse to pair out of the box on most linux systems. To solve this issue ERTM needs to be disabled.

To disable it manually:

root #echo 'Y' > /sys/module/bluetooth/parameters/disable_ertm

This will disable ERTM only until the system is rebooted. To disable it permanently, install the xpadneo kernel module.

root #emerge --ask games-util/xpadneo

In most cases, this will automatically solve the issue. If it doesn't, add this line into xpadneo config manually:

FILE /etc/modprobe.d/xpadneo.conf

options bluetooth disable_ertm=Y

Notebook has a Synopsys DesignWare Controller

Bluetooth support for this controller needs also these options in kernel config^[3]:

KERNEL

Device Drivers  --->
    Character devices  --->
        Serial drivers  --->
            [*] 8250/16550 and compatible serial support
            [*] Support for Synopsys DesignWare 8250 quirks

Resolving firmware problems

It happens that the firmware of bluetooth adapters enters a state where it is unable to pair with a certain (or all) bluetooth devices. Resetting the adapter might solve such problems.

In the case of a laptop with a built-in bluetooth adapter this might be achieved by:

Enter the laptop's firmware settings (BIOS) and disable the built-in adapter
Save settings and restart the laptop
Enter the firmware settings a second time and enable the bluetooth adapter again
Save and restart
Now try to pair the device again

References

[1] Gentoo Forums thread

[2] ttps://github.com/bluez/bluez/issues/236

[3] Gentoo Forums thread

[1]

[2]

[3]

Bluetooth

Contents

Prerequisites

Installation

Kernel

Firmware

USE flags

USE flags for net-wireless/bluez Bluetooth Tools and System Daemons for Linux

Emerge

Configuration

Permissions

Services

OpenRC

systemd

Enabling battery reporting

Usage

Controller setup

Device pairing

hciconfig

Disable Bluetooth

Using udev to disable Bluetooth

Using OpenRC to disable Bluetooth

Disable Bluetooth at kernel level

Utilities

Troubleshooting

TLP and laptop_mode

XBOX ONE controller pairing

Notebook has a Synopsys DesignWare Controller

Resolving firmware problems

See also

References