Bluetooth: Difference between revisions

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(→‎Thinkpad Bluetooth Laser Mouse problems: Moved section to the Bluetooth_mouse page.)
(Moved front-end app options from Config to Install (modeled after PulseAudio Install section). Purpose was to clean up Config to be bluez5 specific. And it gives better structure for the eventual merge with BT Keyboard & BT Headset.)
Line 31: Line 31:
* Some tools such as hcitool and hciconfig have been deprecated upstream, and are no longer included in {{Pkg|bluez-utils}}. Since these tools will no longer be updated, it is recommended that scripts be updated to avoid using them. If you still desire to use them, install {{AUR|bluez-utils-compat}}. See {{Bug|53110}} and [https://www.spinics.net/lists/linux-bluetooth/msg69239.html the Bluez mailing list] for more information. }}
* Some tools such as hcitool and hciconfig have been deprecated upstream, and are no longer included in {{Pkg|bluez-utils}}. Since these tools will no longer be updated, it is recommended that scripts be updated to avoid using them. If you still desire to use them, install {{AUR|bluez-utils-compat}}. See {{Bug|53110}} and [https://www.spinics.net/lists/linux-bluetooth/msg69239.html the Bluez mailing list] for more information. }}


== Configuration via the CLI ==
=== Front-ends ===
==== Command-line ====
* {{App|bluetoothctl|Pairing a device from the shell is one of the simplest and most reliable options.||{{Pkg|bluetooth-utils}}}}
 
==== Graphical front-end ====
The following packages allow for a graphical interface to customize Bluetooth.
 
* {{App|GNOME Bluetooth|[[GNOME]]'s Bluetooth tool.
** {{Pkg|gnome-bluetooth}} provides the back-end
** {{Pkg|gnome-shell}} provides the status monitor applet
** {{Pkg|gnome-control-center}} provides the configuration front-end GUI that can be accessed by typing Bluetooth on the Activities overview, or with the {{ic|gnome-control-center bluetooth}} command.
** You can also launch the {{ic|bluetooth-sendto}} command directly to send files to a remote device.
** To receive files, open the Bluetooth settings panel; you can only receive whilst the Bluetooth panel is open.
** To add a Bluetooth entry to the ''Send To'' menu in Thunar's file properties menu, see instructions [http://docs.xfce.org/xfce/thunar/send-to here]. (The command that needs to be configured is {{ic|bluetooth-sendto %F}}).
|https://wiki.gnome.org/Projects/GnomeBluetooth|}}
 
* {{App|Bluedevil|[[KDE]]'s Bluetooth tool. If there is no Bluetooth icon visible in Dolphin and in the system tray, enable it in the system tray options or add a widget. You can configure Bluedevil and detect Bluetooth devices by clicking the icon. An interface is also available from the KDE System Settings.|https://projects.kde.org/projects/kde/workspace/bluedevil|{{Pkg|bluedevil}}}}
 
* {{App|Blueberry|Linux Mint's spin-off of GNOME Bluetooth, which works in all desktop environments. ''Blueberry'' doesn't support receiving files through Obex Object Push.|https://github.com/linuxmint/blueberry|{{Pkg|blueberry}}}}
 
* {{App|[[Blueman]]|A full featured Bluetooth manager.|https://github.com/blueman-project/blueman|{{ic|blueman-manager}} (graphical settings panel), {{ic|blueman-applet}} (system tray applet)}}
 
== Configuration ==


{{Note|Before using the bluetooth device, make sure that it is not blocked by [[rfkill]].}}
{{Note|Before using the bluetooth device, make sure that it is not blocked by [[rfkill]].}}


=== Bluetoothctl ===
The exact procedure depends on the devices involved and their input functionality.  What follows is a general outline of pairing a device using {{ic|/usr/bin/bluetoothctl}}:
Pairing a device from the shell is one of the simplest and most 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 {{ic|/usr/bin/bluetoothctl}}:


Start the {{ic|bluetoothctl}} interactive command. Input {{ic|help}} to get a list of available commands.
Start the {{ic|bluetoothctl}} interactive command. Input {{ic|help}} to get a list of available commands.
Line 78: Line 99:
  Connection successful
  Connection successful


====Auto power-on after boot====
===Auto power-on after boot===
By default, your Bluetooth adapter will not power on after a reboot. The former method by using {{ic|hciconfig hci0 up}} is deprecated, see the [http://www.bluez.org/release-of-bluez-5-35/ release note]. Now you just need to add the line {{ic|1=AutoEnable=true}} in {{ic|/etc/bluetooth/main.conf}} at the bottom in the {{ic|[Policy]}} section:
By default, your Bluetooth adapter will not power on after a reboot. The former method by using {{ic|hciconfig hci0 up}} is deprecated, see the [http://www.bluez.org/release-of-bluez-5-35/ release note]. Now you just need to add the line {{ic|1=AutoEnable=true}} in {{ic|/etc/bluetooth/main.conf}} at the bottom in the {{ic|[Policy]}} section:
{{hc|1=/etc/bluetooth/main.conf|2=
{{hc|1=/etc/bluetooth/main.conf|2=
Line 84: Line 105:
AutoEnable=true
AutoEnable=true
}}
}}
== Configuration with a graphical front-end ==
The following packages allow for a graphical interface to customize Bluetooth.
=== GNOME Bluetooth ===
[https://wiki.gnome.org/Projects/GnomeBluetooth GNOME Bluetooth] is [[GNOME]]'s Bluetooth tool. The {{Pkg|gnome-bluetooth}} package provides the back-end, {{Pkg|gnome-shell}} provides the status monitor applet, and {{Pkg|gnome-control-center}} provides the configuration front-end GUI that can be accessed by typing Bluetooth on the Activities overview, or with the {{ic|gnome-control-center bluetooth}} command. You can also launch the {{ic|bluetooth-sendto}} command directly to send files to a remote device.
To receive files, open the Bluetooth settings panel; you can only receive whilst the Bluetooth panel is open.
{{Tip|To add a Bluetooth entry to the ''Send To'' menu in Thunar's file properties menu, see instructions [http://docs.xfce.org/xfce/thunar/send-to here]. (The command that needs to be configured is {{ic|bluetooth-sendto %F}}).}}
=== Bluedevil ===
[https://projects.kde.org/projects/kde/workspace/bluedevil Bluedevil] is [[KDE]]'s Bluetooth tool. It can be [[installed]] with the package {{Pkg|bluedevil}} (KDE Plasma 5).
If there is no Bluetooth icon visible in Dolphin and in the system tray, enable it in the system tray options or add a widget. You can configure Bluedevil and detect Bluetooth devices by clicking the icon. An interface is also available from the KDE System Settings.
=== Blueberry ===
''Blueberry'' is an alternative front-end for GNOME Bluetooth, which works in all desktop environments. It can be installed with the {{Pkg|blueberry}} package. It provides a configuration tool (''blueberry'') and a system tray applet (''blueberry-tray'').
{{Note|''Blueberry'' doesn't support receiving files through Obex Object Push, see ''blueman'' below if you want to be able to receive files.}}
=== Blueman ===
[[Blueman]] is a full featured Bluetooth manager. It provides a graphical settings panel {{ic|blueman-manager}} and a system tray applet {{ic|blueman-applet}}. See [[Blueman]] for more details.


== Using Obex for sending and receiving files ==
== Using Obex for sending and receiving files ==

Revision as of 02:01, 15 June 2018

Bluetooth is a standard for the short-range wireless interconnection of cellular phones, computers, and other electronic devices. In Linux, the canonical implementation of the Bluetooth protocol stack is BlueZ.

Installation

Install the bluez and bluez-utils packages. The bluez package provides the Bluetooth protocol stack, and the bluez-utils package provides the bluetoothctl utility.

The generic Bluetooth driver is the btusb Kernel module. Check whether that module is loaded. If it's not, then load the module.

Then start the bluetooth.service systemd unit. You can enable it to start automatically at boot time.

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.
  • Some Bluetooth adapters are bundled with a Wi-Fi card (e.g. Intel Centrino). These require that the Wi-Fi card is firstly enabled (typically a keyboard shortcut on a laptop) in order to make the Bluetooth adapter visible to the kernel.
  • Some Bluetooth cards (e.g. Broadcom) conflict with the network adapter. Thus, you need to make sure that your Bluetooth device get connected before the network service boot.
  • Some tools such as hcitool and hciconfig have been deprecated upstream, and are no longer included in bluez-utils. Since these tools will no longer be updated, it is recommended that scripts be updated to avoid using them. If you still desire to use them, install bluez-utils-compatAUR. See FS#53110 and the Bluez mailing list for more information.

Front-ends

Command-line

  • bluetoothctl — Pairing a device from the shell is one of the simplest and most reliable options.
|| bluetooth-utils

Graphical front-end

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

  • GNOME BluetoothGNOME's Bluetooth tool.
    • gnome-bluetooth provides the back-end
    • gnome-shell provides the status monitor applet
    • 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.
    • You can also launch the bluetooth-sendto command directly to send files to a remote device.
    • To receive files, open the Bluetooth settings panel; you can only receive whilst the Bluetooth panel is open.
    • To add a Bluetooth entry to the Send To menu in Thunar's file properties menu, see instructions here. (The command that needs to be configured is bluetooth-sendto %F).
https://wiki.gnome.org/Projects/GnomeBluetooth ||
  • BluedevilKDE's Bluetooth tool. If there is no Bluetooth icon visible in Dolphin and in the system tray, enable it in the system tray options or add a widget. You can configure Bluedevil and detect Bluetooth devices by clicking the icon. An interface is also available from the KDE System Settings.
https://projects.kde.org/projects/kde/workspace/bluedevil || bluedevil
  • Blueberry — Linux Mint's spin-off of GNOME Bluetooth, which works in all desktop environments. Blueberry doesn't support receiving files through Obex Object Push.
https://github.com/linuxmint/blueberry || blueberry
  • Blueman — A full featured Bluetooth manager.
https://github.com/blueman-project/blueman || blueman-manager (graphical settings panel), blueman-applet (system tray applet)

Configuration

Note: Before using the bluetooth device, make sure that it is not blocked by rfkill.

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. Input help to get a list of available commands.

  • Possibly select a default controller by inputting select MAC Address
  • Turn the power to the controller on by entering power on. It is off by default and will turn off again each reboot, see #Auto power-on after boot.
  • 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 or choose a specific agent: if you press tab twice after agent you should see a list of available agents, e.g. DisplayOnly KeyboardDisplay NoInputNoOutput DisplayYesNo KeyboardOnly off 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]# power on
Changing power on succeeded
[CHG] Controller 00:10:20:30:40:50 Powered: yes
[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
[bluetooth]# connect 00:12:34:56:78:90
Attempting to connect to 00:12:34:56:78:90
[CHG] Device 00:12:34:56:78:90 Connected: yes
Connection successful

Auto power-on after boot

By default, your Bluetooth adapter will not power on after a reboot. The former method by using hciconfig hci0 up is deprecated, see the release note. Now you just need to add the line AutoEnable=true in /etc/bluetooth/main.conf at the bottom in the [Policy] section:

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

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 obexfsAUR and mount supported phones by running:

$ obexfs -b MAC_address_of_device /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.

To send a file to a device run the command:

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

To retrieve a file from a device run the command:

$ obexftp -b MAC_address_of_device -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-pushAUR to send files to this device:

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

Audio

In order to be able to use audio equipment like bluetooth headphones or speakers, you need to install the additional pulseaudio-bluetooth package.

Please have a look at the Bluetooth headset page for more information about bluetooth audio and bluetooth headsets.

Using your computer's speakers as a bluetooth headset

In order to enable your system to be detected as an A2DP sink (e.g. to play music from your phone via your computer speakers), add the following to the file /etc/bluetooth/audio.conf (create it if not present):

[General]
Enable=Source

More info in:

Troubleshooting

Shell command _____ is missing from bluez-utils

Some tools have been marked as deprecated and removed from the package. At this time they are still available in the AUR package bluez-utils-compatAUR. Their functionality is partially covered by new tools, while some things have yet to be implemented with the new D-Bus API:

Deprecated tool Most likely replacement
gatttool btgatt-client, D-Bus Gatt API
hciattach btattach
hciconfig btmgmt (and bluetoothctl?)
hcidump btmon (and btsnoop)
hcitool missing, D-Bus Device API available
rfcomm missing, implement with D-Bus Profile1 API?
ciptool
sdptool missing, functionality seems to be scattered over different D-Bus objects: Profile, Advertising, and the UUIDs arrays in device and adapter.

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 make sure that the XDG user directories exist.

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 you have plugged 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

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

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)

Audio devices start to skip at short distance from dongle

If other devices share the same USB host, they can interrupt communication with audio devices. Make sure it is the only device attached to its bus. For example:

$ lsusb
Bus 002 Device 002: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 048d:1345 Integrated Technology Express, Inc. Multi Cardreader
Bus 001 Device 003: ID 0424:a700 Standard Microsystems Corp. 2 Port Hub
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

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 you are 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

Alternatively, you can install the bluez-hid2hci package. When you connect your Logitech dongle it will automatically switch.

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:

# 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.

HSP/HFP profiles

bluez5 removed support for the HSP/HFP profiles (telephony headset for TeamSpeak, Skype, etc.). You need to install PulseAudio (>= version 6) or another application that implements HSP/HFP itself.

Foxconn / Hon Hai / Lite-On Broadcom device

Some of these devices require the firmware to be flashed into the device at boot. The firmware is not provided but can converted from a Microsoft Windows .hex file into a .hcd using hex2hcd (which is installed with bluez-utils).

In order to get the right .hex file, try searching the device vendor:product code obtained with lsusb, for example:

   ...
   Bus 002 Device 004: ID 04ca:2006 Lite-On Technology Corp. Broadcom BCM43142A0 Bluetooth Device
   ...

or

   Bus 004 Device 004: Id 0489:e031 Foxconn / Hon Hai

Alternatively, boot into Windows (a virtual machine installation will suffice) and get the firmware name from the Device Manager utility. If you want to know the model of your device but cannot see it in lsusb, you might see it in lsusb -v as iProduct.

The .hex file can be extracted from the downloaded Windows driver without having to run Windows for it. Download the right driver, for example Bluetooth Widcomm (listed among the drivers for Lifebook P771), which contains the drivers for many Broadcomm devices. In case of Bluetooth Widcomm, the driver is a self-extracting RAR archive, so it can be extracted using unrar x. To find out which of the many .hex files is the right one for you, look in the file Win32/bcbtums-win7x86-brcm.inf and search for [RAMUSBE031.CopyList], where E031 should be replaced with the product code (the second hex number in lsusb) of your device in upper-case. Underneath you should see the file name of the right .hex file.

Once you have the .hcd file, copy it into /lib/firmware/brcm/BCM.hcd - this filename is suggested by dmesg and it may change in your case so check your dmesg output in order to verify. Then reload the btusb module:

# rmmod btusb
# modprobe btusb

In some cases (with older kernels?), you have to flash the .hcd file with the brcm_patchram_plus utility, provided by brcm_patchram_plus-gitAUR[broken link: Template:Aur-mirror]. First, make sure in dmesg that the device is recognized by btusb as a bluetooth device. Then, run the following (replace 04ca 2006 with your vendor product pair):

# echo '04ca 2006' > /sys/bus/usb/drivers/btusb/new_id
    

Turn on the device:

# hciconfig hci0 up

Flash the firmware:

# brcm_patchram_plus_usb --patchram fw-04ca_2006.hcd hci0

The device should now be available. See BBS#162688 for information on making these changes persistent.

Device connects, then disconnects after a few moments

If you see messages like the following in journalctl output, and your device fails to connect or disconnects shortly after connecting:

bluetoothd: Unable to get connect data for Headset Voice gateway: getpeername: Transport endpoint is not connected (107)
bluetoothd: connect error: Connection refused (111)

This may be because you have already paired the device with another operating system using the same bluetooth adapter (e.g., dual-booting). Some devices can't handle multiple pairings associated with the same MAC address (i.e., bluetooth adapter). You can fix this by re-pairing the device. Start by removing the device:

$ bluetoothctl
[bluetooth]# devices
Device XX:XX:XX:XX:XX:XX My Device
[bluetooth]# remove XX:XX:XX:XX:XX:XX

Then restart bluetooth.service, turn on your bluetooth adapter, make your device discoverable, re-scan for devices, and re-pair your device. Depending on your bluetooth manager, you may need to perform a full reboot in order to re-discover the device.

Device does not connect with an error in journal

If you see a message like the following in journalctl output while trying to connect to a device:

a2dp-source profile connect failed for 9C:64:40:22:E1:3F: Protocol not available

try installing pulseaudio-bluetooth and restarting pulseaudio. This error can manifest even while using only file transfer.

Device does not show up in scan

Some devices using bluetooth low energy do not appear when scanning with bluetoothctl, for example the Logitech MX Master. The simplest way I've found to connect them is by installing bluez-utils-compatAUR, then start bluetooth.service and do:

# bluetoothctl
[NEW] Controller (MAC) myhostname [default]
[bluetooth]# power on
[CHG] Controller (MAC) Class: 0x0c010c
Changing power on succeeded
[CHG] Controller (MAC) Powered: yes
[bluetooth]# scan on
Discovery started
[CHG] Controller (MAC) Discovering: yes

In another terminal:

# hcitool lescan

Wait until your device shows up, then Ctrl+C hcitool. bluetoothctl should now see your device and pair normally.