Difference between revisions of "Bluetooth"

Revision as of 13:16, 28 February 2014

Installation

Install the Bluetooth protocol stack bluez and the bluez-utils package which provides the bluetoothctl utility from the official repositories. The dbus daemon, which is started automatically by systemd, is used to read settings and for PIN pairing, while the bluetooth daemon is required for the Bluetooth protocol.

To start the bluetooth systemd service use the command:

# systemctl start bluetooth

To enable the bluetooth service at boot time use the command:

# systemctl enable bluetooth

Note: By default the bluetooth daemon will only give out bnep0 devices to users that are a member of the lp group. Make sure to add your user to that group if you intend to connect to a bluetooth tether. You can change the group that is required in the file /etc/dbus-1/system.d/bluetooth.conf.

Note: Some Bluetooth adapters are bundled with a Wi-Fi card (e.g. Intel Centrino). These require that the Wi-Fi card is first enabled (typically a keyboard shortcut on a laptop) in order to make the Bluetooth adapter visible to the kernel.

Configuration via the CLI

Bluetoothctl

Pairing a device from the shell is one of the most simplistic and reliable options. The exact procedure depends on the devices involved and their input functionality. What follows is a general outline of pairing a device using /usr/bin/bluetoothctl:

Start the bluetoothctl interactive command. There one can input help to get a list of available commands.

Turn the power to the controller on by entering power on. It is off by default.
Enter devices to get the MAC Address of the device with which to pair.
Enter device discovery mode with scan on command if device is not yet on the list.
Turn the agent on with agent on.
Enter pair MAC Address to do the pairing (tab completion works).
If using a device without a PIN, one may need to manually trust the device before it can reconnect successfully. Enter trust MAC Address to do so.
Finally, use connect MAC_address to establish a connection.

An example session may look this way:

# bluetoothctl 
[NEW] Controller 00:10:20:30:40:50 pi [default]
[bluetooth]# agent KeyboardOnly 
Agent registered
[bluetooth]# default-agent 
Default agent request successful
[bluetooth]# scan on
Discovery started
[CHG] Controller 00:10:20:30:40:50 Discovering: yes
[NEW] Device 00:12:34:56:78:90 myLino
[CHG] Device 00:12:34:56:78:90 LegacyPairing: yes
[bluetooth]# pair 00:12:34:56:78:90
Attempting to pair with 00:12:34:56:78:90
[CHG] Device 00:12:34:56:78:90 Connected: yes
[CHG] Device 00:12:34:56:78:90 Connected: no
[CHG] Device 00:12:34:56:78:90 Connected: yes
Request PIN code
[agent] Enter PIN code: 1234
[CHG] Device 00:12:34:56:78:90 Paired: yes
Pairing successful
[CHG] Device 00:12:34:56:78:90 Connected: no

In order to have the device active after a reboot, a udev rule is needed: /etc/udev/rules.d/10-local.rules

# Set bluetooth power up
ACTION=="add", KERNEL=="hci0", RUN+="/usr/bin/hciconfig hci0 up"

After a suspend/resume-cycle, the device can be powered off automatically using something like this systemd service:

/etc/systemd/system/bluetooth-auto-power@.service

[Unit]
Description=Bluetooth auto power on
After=bluetooth.service sys-subsystem-bluetooth-devices-%i.device suspend.target

[Service]
Type=oneshot
#We could also do a 200 char long call to bluez via dbus. Except this does not work since bluez does not react to dbus at this point of the resume sequence and I do not know how I get this service to run at a time it does. So we just ignore bluez and force %i up using hciconfig. Welcome to the 21st century.
#ExecStart=/usr/bin/dbus-send --system --type=method_call --dest=org.bluez /org/bluez/%I org.freedesktop.DBus.Properties.Set string:org.bluez.Adapter1 string:Powered variant:boolean:true
ExecStart=/usr/bin/hciconfig %i up

[Install]
WantedBy=suspend.target

Configuration with a Graphical Front-end

The following packages allow for a graphical interface to customize Bluetooth.

GNOME Bluetooth

GNOME Bluetooth is a fork of the old bluez-gnome and is focused on integration with the GNOME desktop environment. The gnome-bluetooth package provides the back-end, gnome-shell provides the status monitor applet, and gnome-control-center provides the configuration front-end GUI that can be accessed by typing Bluetooth on the Activities overview, or with the gnome-control-center bluetooth command.

Users who are not using GNOME Shell can install gnome-bluetooth-applet-git^AUR from AUR, which provides the old status monitor applet, and allows setup devices and transfer of files by clicking the Bluetooth icon. Just make sure that bluetooth-applet is autostarted with your session.

You can also launch the following commands directly:

bluetooth-sendto: send files to a remote device
bluetooth-wizard: for new devices to be paired

To add a Bluetooth entry to the SendTo menu in Thunar's file properties menu, see instructions here. (The command that needs to be configured is bluetooth-sendto %F)

BlueDevil

The Bluetooth tool for KDE is BlueDevil. It can be installed with the package bluedevil, available in the official repositories.

Make sure bluetooth daemon is running, as described above. A Bluetooth icon should be visible in both Dolphin and in the system tray, from which users may configure BlueDevil and detect Bluetooth devices by clicking the icon. An interface is also available from the KDE System Settings.

Using Obex for sending and receiving files

ObexFS

Another option, rather than using KDE or Gnome Bluetooth packages, is ObexFS which allows for the mounting of phones which are treated like any other filesystem.

Note: To use ObexFS, one needs a device that provides an ObexFTP service.

Install obexfs and mount supported phones by running:

$ obexfs -b devices_MAC_address /mountpoint

Once you have finished, to unmount the device use the command:

$ fusermount -u /mountpoint

For more mounting options see http://dev.zuckschwerdt.org/openobex/wiki/ObexFs

Note: Ensure that the bluetooth device you are mounting is not set to mount read-only. You should be able to do this from the device's settings. If the device is mounted read-only you may encounter a permissions error when trying to transfer files to the device.

ObexFTP Transfers

If your device supports the Obex FTP service but you do not wish to mount the device you can transfer files to and from the device using the obexftp command.

Tip: If you installed obexfs earlier then obexftp should have also been installed as a dependency.

To send a file to a device run the command:

$ obexftp -b devices_MAC_address -p /path/to/file

To retrieve a file from a device run the command:

$ obexftp -b devices_MAC_address -g filename

Note: Ensure that the file you are retrieving is in the device's exchange folder. If the file is in a subfolder of the exchange folder then provide the correct path in the command.

Obex Object Push

For devices that do not support Obex FTP service, check if Obex Object Push is supported.

# sdptool browse XX:XX:XX:XX:XX:XX

Read the output, look for Obex Object Push, remember the channel for this service. If supported, one can use ussp-push to send files to this device:

# ussp-push XX:XX:XX:XX:XX:XX@CHANNEL file wanted_file_name_on_phone

Examples

All examples have been moved to the bluez4 article. They need to be checked and fixed for use with bluez5.

Troubleshooting

gnome-bluetooth

If you see this when trying to enable receiving files in bluetooth-properties:

Bluetooth OBEX start failed: Invalid path
Bluetooth FTP start failed: Invalid path

Then install xdg-user-dirs and issue:

$ xdg-user-dirs-update

You can edit the paths using:

$ vi ~/.config/user-dirs.dirs

Bluetooth USB Dongle

If you are using a USB dongle, you should check that your Bluetooth dongle is recognized. You can do that by running journalctl -f when plugging in the USB dongle (or inspecting /var/log/messages.log). It should look something like the following (look out for hci):

Feb 20 15:00:24 hostname kernel: [ 2661.349823] usb 4-1: new full-speed USB device number 3 using uhci_hcd
Feb 20 15:00:24 hostname bluetoothd[4568]: HCI dev 0 registered
Feb 20 15:00:24 hostname bluetoothd[4568]: Listening for HCI events on hci0
Feb 20 15:00:25 hostname bluetoothd[4568]: HCI dev 0 up
Feb 20 15:00:25 hostname bluetoothd[4568]: Adapter /org/bluez/4568/hci0 has been enabled

For a list of supported hardware please refer to the Resource section on this page.

If you only get the first two lines, you may see that it found the device but you need to bring it up. Example:

hciconfig -a hci0

hci0:	Type: USB
	BD Address: 00:00:00:00:00:00 ACL MTU: 0:0 SCO MTU: 0:0
	DOWN 
	RX bytes:0 acl:0 sco:0 events:0 errors:0
        TX bytes:0 acl:0 sco:0 commands:0 errors:

# hciconfig hci0 up

hciconfig -a hci0

hci0:	Type: USB
	BD Address: 00:02:72:C4:7C:06 ACL MTU: 377:10 SCO MTU: 64:8
	UP RUNNING 
	RX bytes:348 acl:0 sco:0 events:11 errors:0
        TX bytes:38 acl:0 sco:0 commands:11 errors:0

If this fails with an error like:

Operation not possible due to RF-kill

it could be due either to the rfkill utility, in which case it should be resolved with

# rfkill unblock all

or, it could simply be the hardware switch of the computer. The hardware bluetooth switch (at least sometimes) controls access to USB bluetooth dongles also. Flip/press this switch and try bringing the device up again.

To verify that the device was detected you can use hcitool which is part of the bluez-utils. You can get a list of available devices and their identifiers and their MAC address by issuing:

$ hcitool dev

Devices:
        hci0	00:1B:DC:0F:DB:40

More detailed information about the device can be retrieved by using hciconfig.

$ hciconfig -a hci0

hci0:   Type: USB
        BD Address: 00:1B:DC:0F:DB:40 ACL MTU: 310:10 SCO MTU: 64:8
        UP RUNNING PSCAN ISCAN
        RX bytes:1226 acl:0 sco:0 events:27 errors:0
        TX bytes:351 acl:0 sco:0 commands:26 errors:0
        Features: 0xff 0xff 0x8f 0xfe 0x9b 0xf9 0x00 0x80
        Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
        Link policy: RSWITCH HOLD SNIFF PARK
        Link mode: SLAVE ACCEPT 
        Name: 'BlueZ (0)'
        Class: 0x000100
        Service Classes: Unspecified
        Device Class: Computer, Uncategorized
        HCI Ver: 2.0 (0x3) HCI Rev: 0xc5c LMP Ver: 2.0 (0x3) LMP Subver: 0xc5c
        Manufacturer: Cambridge Silicon Radio (10)

Logitech Bluetooth USB Dongle

There are Logitech dongles (ex. Logitech MX5000) that can work in two modes Embedded and HCI. In embedded mode dongle emulates a USB device so it seems to your PC that your using a normal USB mouse/keyoard.

If you hold the little red Button on the USB BT mini-receiver it will enable the other mode. Hold the red button on the BT dongle and plug it into the computer, and after 3-5 seconds of holding the button, the Bluetooth icon will appear in the system tray. Discussion

hcitool scan: Device not found

On some Dell laptops (e.g. Studio 15) you have to switch the Bluetooth mode from HID to HCI. Install the bluez-hid2hci package, then udev should do this automatically. Alternatively, you can run this command to switch to HCI manually:

# /usr/lib/udev/hid2hci

If the device will not show up and you have a Windows operating system on your machine, try booting it and enable the bluetooth adapter from windows.

Sometimes also this simple command helps:

# hciconfig hci0 up

rfkill unblock: Do not unblock

If your device still soft blocked and you run connman.

Try this: $ connmanctl enable bluetooth

My computer is not visible

Cannot discover computer from your phone? Enable PSCAN and ISCAN:

# enable PSCAN and ISCAN
$ hciconfig hci0 piscan 
# check it worked

$ hciconfig

hci0:   Type: USB
        BD Address: 00:12:34:56:78:9A ACL MTU: 192:8 SCO MTU: 64:8
        UP RUNNING PSCAN ISCAN
        RX bytes:20425 acl:115 sco:0 events:526 errors:0
        TX bytes:5543 acl:84 sco:0 commands:340 errors:0

Note: Check DiscoverableTimeout and PairableTimeout in /etc/bluetooth/main.conf

Try changing device class in /etc/bluetooth/main.conf as following:

# Default device class. Only the major and minor device class bits are
# considered.
#Class = 0x000100 (from default config)
Class = 0x100100

This was the only solution to make my computer visible for my phone.

Logitech keyboard does not pair

If you do not get the passkey when you try to pair your Logitech keyboard, type the following command:

$ sudo hciconfig hci0 sspmode 0

If after pairing, the keyboard still does not connect, check the output of hcidump -at. If the latter indicates repeatedly connections-disconnections like the following message:

   status 0x00 handle 11 reason 0x13
   Reason: Remote User Terminated Connection

then, the only solution for now is to install the old Bluetooth stack.