Bluetooth

Enabling Bluetooth support

To enable support for Bluetooth devices, add hardware.bluetooth.enable to /etc/nixos/configuration.nix:

{
  ...
  hardware.bluetooth.enable = true;
  ...
}

Tip

In order to affect your NixOS system by your nix-language-specific changes you must first evaluate it:

$ nixos-rebuild switch --use-remote-sudo

Pairing Bluetooth devices

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In order to use Bluetooth devices, they must be paired with your NixOS machine. Heavier desktop environments will usually provide a Bluetooth management GUI which you can use to pair devices.

If your desktop environment does not provide such a GUI, you can install the blueman package. This provides a tray icon process (blueman-applet) and a GUI management application (blueman-manager).

Pairing devices from the command line

Alternatively, Bluetooth devices can be paired from the command line using bluetoothctl.

$ bluetoothctl
[bluetooth] # power on
[bluetooth] # agent on
[bluetooth] # default-agent
[bluetooth] # scan on
...put device in pairing mode and wait [hex-address] to appear here...
[bluetooth] # pair [hex-address]
[bluetooth] # connect [hex-address]

Using Bluetooth headsets with PulseAudio

To allow Bluetooth audio devices to be used with PulseAudio, amend /etc/nixos/configuration.nix as follows:

{
  ...
  hardware.pulseaudio = {
    enable = true;

    # NixOS allows either a lightweight build (default) or full build of PulseAudio to be installed.
    # Only the full build has Bluetooth support, so it must be selected here.
    package = pkgs.pulseaudioFull;
  };

  hardware.bluetooth.enable = true;
  ...
}

Tip

In order to affect your NixOS system by your nix-language-specific changes you must first evaluate it:

$ nixos-rebuild switch --use-remote-sudo

You will need to restart PulseAudio; try systemctl --user daemon-reload; systemctl --user restart pulseaudio.

You can verify that PulseAudio has loaded the Bluetooth module by running pactl list | grep -i 'Name.*module.*blue'; Bluetooth modules should be present in the list.

Enabling A2DP Sink

Modern headsets will generally try to connect using the A2DP profile. To enable this for your bluetooth connection, add the following to /etc/nixos/configuration.nix

{
...
hardware.bluetooth.extraConfig = "
  [general]
  Enable=Source,Sink,Media,Socket
"
...
}

Managing audio devices

pavucontrol can be used to reconfigure the device:

• To enable A2DP, change the profile to “High Fidelity Playback (A2DP Sink)” on the “Configuration” tab.
• To set the device as the default audio output, select “set as fallback” on the “Output Devices” tab.

Alternatively, the device can be configured via the command line:

• To enable A2DP, run:

  $ pacmd set-card-profile "$(pactl list cards short | egrep -o bluez_card[[:alnum:]._]+)" a2dp_sink
  

• To set the device as the default audio output, run:

  $ pacmd set-default-sink "$(pactl list sinks short | egrep -o bluez_sink[[:alnum:]._]+)"
  

Troubleshooting

USB device needs to be unplugged/re-plugged after suspend

Some USB device/host combinations don't play well with the suspend/resume cycle, and need to be unplugged and then re-plugged to work again.

It is possible to simulate a unplug/re-plug cycle using the /sys filesystem.

This gist provides a script and instructions to set-up a workaround for these devices.

When connecting to an audio device: Failed to connect: org.bluez.Error.Failed

You need to use pulseaudioFull, see #Using Bluetooth headsets with PulseAudio.

Bluetooth fails to power on with Failed to set power on: org.bluez.Error.Blocked

If journalctl -eu bluetooth shows Failed to set mode: Blocked through rfkill (0x12), rfkill might be blocking it:

$ rfkill
ID TYPE      DEVICE      SOFT      HARD
 1 wlan      phy0   unblocked unblocked
37 bluetooth hci0   blocked unblocked

Unblock it first:

$ sudo rfkill unblock bluetooth

See also

• Scripting PulseAudio, Bluetooth, JACK
• Bluetooth (Arch Linux Wiki)