Can't enable bluetooth after a software update

The Software Update GUI told me that there are new updates, and I installed them. It told me after the installation that I have to restart the system (maybe it is a hint?). Since then I can not enable bluetooth… There were no kernel updates. The only suspicious thing is that bluez-qt has a different version than the other bluez packages.

What could I do to solve the issue, or at least to get more information about the problem?

The output of journalctl -f after inserting the bluetooth dongle:

Nov 20 19:24:35 adrian kernel: usb 1-7.2: new full-speed USB device number 15 using xhci_hcd
Nov 20 19:24:36 adrian kernel: usb 1-7.2: New USB device found, idVendor=0bda, idProduct=8771, bcdDevice= 2.00
Nov 20 19:24:36 adrian kernel: usb 1-7.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Nov 20 19:24:36 adrian kernel: usb 1-7.2: Product: Bluetooth Radio
Nov 20 19:24:36 adrian kernel: usb 1-7.2: Manufacturer: Realtek
Nov 20 19:24:36 adrian kernel: usb 1-7.2: SerialNumber: 00E04C239987
Nov 20 19:24:36 adrian systemd[1]: Starting Load/Save RF Kill Switch Status...
Nov 20 19:24:36 adrian kernel: Bluetooth: hci0: RTL: examining hci_ver=0a hci_rev=000b lmp_ver=0a lmp_subver=8761
Nov 20 19:24:36 adrian kernel: Bluetooth: hci0: RTL: rom_version status=0 version=1
Nov 20 19:24:36 adrian kernel: Bluetooth: hci0: RTL: loading rtl_bt/rtl8761b_fw.bin
Nov 20 19:24:36 adrian kernel: Bluetooth: hci0: RTL: loading rtl_bt/rtl8761b_config.bin
Nov 20 19:24:36 adrian kernel: Bluetooth: hci0: RTL: cfg_sz 25, total sz 21389
Nov 20 19:24:36 adrian kernel: Bluetooth: hci0: RTL: fw version 0x0d99646b
Nov 20 19:24:36 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSink/sbc
Nov 20 19:24:36 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc
Nov 20 19:24:36 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSink/sbc_xq_453
Nov 20 19:24:36 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc_xq_453
Nov 20 19:24:36 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSink/sbc_xq_512
Nov 20 19:24:36 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc_xq_512
Nov 20 19:24:36 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSink/sbc_xq_552
Nov 20 19:24:36 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc_xq_552
Nov 20 19:24:36 adrian upowerd[1374]: treating change event as add on /sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/usb1/1-7/1-7.2
Nov 20 19:24:36 adrian systemd[1]: Started Load/Save RF Kill Switch Status.
Nov 20 19:24:36 adrian audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=systemd-rfkill comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Nov 20 19:24:36 adrian systemd[1106]: Reached target Bluetooth.
Nov 20 19:24:36 adrian systemd[1]: Reached target Bluetooth Support.
Nov 20 19:24:36 adrian kernel: audit: type=1130 audit(1637432676.787:242): pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=systemd-rfkill comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Nov 20 19:24:41 adrian systemd[1]: systemd-rfkill.service: Deactivated successfully.
Nov 20 19:24:41 adrian audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=systemd-rfkill comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Nov 20 19:24:41 adrian kernel: audit: type=1131 audit(1637432681.794:243): pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=systemd-rfkill comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'

Further debugging information:

zoltan@adrian ~ $ inxi -Fazy
System:
  Kernel: 5.12.19-1-MANJARO x86_64 bits: 64 compiler: gcc v: 11.1.0
  parameters: BOOT_IMAGE=/boot/vmlinuz-5.12-x86_64
  root=UUID=51ada9e3-e864-4f90-a085-772e9ba393fb rw quiet apparmor=1
  security=apparmor resume=UUID=74ceb443-e800-4cd8-8259-072d27a86404
  udev.log_priority=3
  Desktop: KDE Plasma 5.23.3 tk: Qt 5.15.2 wm: kwin_x11 vt: 1 dm: SDDM
  Distro: Manjaro Linux base: Arch Linux
  ......
Bluetooth:
  Device-1: Realtek Bluetooth Radio type: USB driver: btusb v: 0.8
  bus-ID: 1-7.2:13 chip-ID: 0bda:8771 class-ID: e001 serial: <filter>
  Report: rfkill ID: hci0 rfk-id: 2 state: up address: see --recommends
  ......

zoltan@adrian ~ $ sudo /usr/lib/bluetooth/bluetoothd -n -d
bluetoothd[4684]: Bluetooth daemon 5.62
....
D-Bus setup failed: Name already in use
bluetoothd[4684]: src/main.c:main() Unable to get on D-Bus


zoltan@adrian ~ $ bluetoothctl show
Controller 00:E0:4C:AE:42:03 (public)
        Name: adrian
        Alias: adrian
        Class: 0x00000000
        Powered: no
        Discoverable: no
        DiscoverableTimeout: 0x000000b4
        Pairable: yes
       .......


zoltan@adrian ~ $ systemctl status bluetooth
● bluetooth.service - Bluetooth service
     Loaded: loaded (/usr/lib/systemd/system/bluetooth.service; enabled; vendor preset: disabled)
     Active: active (running) since Sat 2021-11-20 18:48:17 CET; 24min ago
       Docs: man:bluetoothd(8)
   Main PID: 2184 (bluetoothd)
     Status: "Running"
      Tasks: 1 (limit: 18446)
     Memory: 2.2M
        CPU: 32ms
     CGroup: /system.slice/bluetooth.service
             └─2184 /usr/lib/bluetooth/bluetoothd

Nov 20 18:56:55 adrian bluetoothd[2184]: Endpoint unregistered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc_xq_552
Nov 20 18:57:01 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSink/sbc
Nov 20 18:57:01 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc
Nov 20 18:57:01 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSink/sbc_xq_453
Nov 20 18:57:01 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc_xq_453
Nov 20 18:57:01 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSink/sbc_xq_512
Nov 20 18:57:01 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc_xq_512
Nov 20 18:57:01 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSink/sbc_xq_552
Nov 20 18:57:01 adrian bluetoothd[2184]: Endpoint registered: sender=:1.63 path=/MediaEndpoint/A2DPSource/sbc_xq_552
Nov 20 19:02:02 adrian bluetoothd[2184]: Failed to set mode: Failed (0x03)

zoltan@adrian ~ $ bluetooth
bluetooth = on
zoltan@adrian ~ $ pamac search bluez
.....
bluez-utils                                                                 [Installed] 5.62-1                   extra 
    Development and debugging utilities for the bluetooth protocol stack
bluez-qt                                                                    [Installed] 5.88.0-1                 extra 
    Qt wrapper for Bluez 5 DBus API
bluez-libs                                                                  [Installed] 5.62-1                   extra 
    Deprecated libraries for the bluetooth protocol stack
bluez-hcitool                                                               [Installed] 5.58-1                   AUR 
    deprecated hcitool from bluez
bluez                                                                       [Installed] 5.62-1                   extra 
    Daemons for the bluetooth protocol stack

Please change kernel, kernel 5.12 is eol.

I moved to kernel version 5.15.2-2. Nothing else changed.

I’ve just serendipitously observed, that if I restart the already working bluetooth.service with systemctl, then I can enable the bluetooth in the Settings… Even though the service was already running after boot.