Bluetooth is a short range wireless protocol that is used to connect to various low bandwidth I/O devices (like keyboards, mice, headsets). Newer versions have a low-energy mode with a slightly higher bandwidth and range.
The Bluetooth solution is composed of a userspace daemon, bluetoothd, that communicates through a management port in the kernel to the hardware drivers. Applications that want to communicate with the bluetoothd daemon do so over a d-bus api. This includes the various GNOME bluetooth applets.
Identifying Bluetooth Problems
Was the bluetooth hardware found?
- Make sure bluetooth was found and enabled (note hci0: and 'UP RUNNING'):
$ hciconfig hci0: Type: Primary Bus: USB BD Address: xx:xx:xx:xx:xx:xx ACL MTU: 1021:4 SCO MTU: 96:6 UP RUNNING PSCAN RX bytes:15047 acl:0 sco:0 events:2433 errors:0 TX bytes:599323 acl:0 sco:0 commands:2431 errors:0
- If the command returns nothing (no hci: info), then there is a hardware issue
$ lsusb -v | grep Bluetooth | grep DeviceProtocol bDeviceProtocol 1 Bluetooth
- If the lsusb command returns nothing, there is no hardware, a dmesg output would be needed
- If the lsusb commands returns Bluetooth, then check for attached driver
$ lsusb -t | grep Wireless |__ Port 4: Dev 4, If 1, Class=Wireless, Driver=btusb, 12M |__ Port 4: Dev 4, If 0, Class=Wireless, Driver=btusb, 12M
- If Driver is empty,
lsusb -voutput would be needed to add ids
- If hciconfig shows output but not UP
$ hciconfig up
- List of paired devices:
$ bluetoothctl [bluetooth]# show [bluetooth]# devices [bluetooth]# info <mac addr of any device you have problems with>
Is the bluetoothd daemon running?
- Verify under systemd bluetooth is 'Active' and 'enabled'
$ systemctl status bluetooth ● bluetooth.service - Bluetooth service Loaded: loaded (/usr/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled) Active: active (running) since Wed 2017-10-04 16:07:40 EDT; 1 day 22h ago Docs: man:bluetoothd(8) Main PID: 27427 (bluetoothd) Status: "Running" Tasks: 1 (limit: 4915) CGroup: /system.slice/bluetooth.service └─27427 /usr/libexec/bluetooth/bluetoothd
- Verify obex is configured to run (to transfer files from phone)
$ systemctl --global --user is-enabled obex enabled
Most bluetooth problems happen in the bluez package (bluetoothd), ie the userspace daemon.
- Enabling bluetoothd debugging
$ \<edit\> /usr/lib/systemd/system/bluetooth.service \<add '-d' to ExecStart line as option to bluetoothd\> \<save and quit\> $ systemctl daemon-reload $ systemctl restart bluetooth
Debugging is enabled and can help pinpoint where some of the bluetooth problems are
- Capture the logs to put in bugzilla report
$ journalctl -r -u bluetooth > /tmp/bluetoothd.out
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. You might be able to resolve such problems by resetting your adapter.
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