bluetooth usb dongle cambridge silicon radio

Troubleshooting Bluetooth Connectivity Issues with a Cambridge Silicon Radio Bluetooth USB Dongle

I recently installed a Bluetooth USB dongle from Cambridge Silicon Radio (CSR) on my Ubuntu machine and was excited to test its functionality. After installing the necessary drivers and rebooting my system, I checked the kernel version using `uname -r` and verified that it was running Linux 5.8.13-050813-generic.

To ensure that I had the latest stable kernel version installed, I visited the Ubuntu Mainline Kernel Installer website and clicked on the last stable kernel version available, which was also 5.8.13. Fortunately, the installation process was successful, and my Bluetooth USB dongle was working as expected.

However, after pairing my Ubuntu machine with a 5.0 speaker and my LG smartphone, I encountered some issues. Despite successfully pairing the devices, I was unable to establish a connection between them. Specifically, I was unable to send pictures from Ubuntu to my smartphone or vice versa.

To troubleshoot the issue, I used the `systemctl status bluetooth` command to check the status of the Bluetooth service. The output indicated that the service was active and running, but there were some errors related to setting the mode:

```

Loaded: loaded (/lib/systemd/system/rvice enabled vendor preset: enabled)

Active: active (running) since Sat 19:02:12 -05 10min ago

Oct 03 19:02:12 PC bluetoothd: Bluetooth daemon 5.53

Oct 03 19:02:11 PC systemd: Starting Bluetooth service.

Oct 03 19:02:14 PC bluetoothd: Failed to set mode: Blocked through rfkill (0x12)

Oct 03 19:02:14 PC bluetoothd: Endpoint registered: sender=:1.75 path=/MediaEndpoint/A2DPSource/sbc

Oct 03 19:02:14 PC bluetoothd: Endpoint registered: sender=:1.75 path=/MediaEndpoint/A2DPSink/sbc

Oct 03 19:02:13 PC bluetoothd: Failed to set mode: Blocked through rfkill (0x12)

Oct 03 19:02:12 PC bluetoothd: Bluetooth management interface 1.17 initialized

Oct 03 19:02:12 PC bluetoothd: Starting SDP server

Oct 03 19:02:12 PC systemd: Started Bluetooth service.

```

The error message 'Failed to set mode: Blocked through rfkill (0x12)' suggested that there was a problem with the rfkill module, which is responsible for blocking or unblocking certain functions.

To further troubleshoot the issue, I used the `hciconfig -a` command to check the status of my Bluetooth device. The output indicated that my device was a primary bus USB Bluetooth device from Cambridge Silicon Radio (CSR):

```

hci0: Type: Primary Bus: USB Bluetooth: L2CAP socket layer initialized

Bluetooth: HCI device and connection manager initialized

sudo dmesg | grep -i bluetooth:

Bluetooth: Core ver 2.22

Manufacturer: Cambridge Silicon Radio (10)

Bluetooth: hci0: inquiry failed: status 0x0c

Bluetooth: RFCOMM socket layer initialized

Bluetooth: BNEP socket layer initialized

Bluetooth: BNEP filters: protocol multicast

Bluetooth: BNEP (Ethernet Emulation) ver 1.3

Bluetooth: hci0: CSR: Unbranded CSR clone detected adding workarounds.

```

The output also indicated that there was a problem with the inquiry process, which is used to search for nearby Bluetooth devices.

In conclusion, while my Cambridge Silicon Radio Bluetooth USB dongle worked initially after installation, I encountered some issues when trying to establish connections between my Ubuntu machine and other Bluetooth devices. The error messages suggested that there were problems with the rfkill module and the inquiry process. By using various troubleshooting commands, I was able to identify the source of the issue and potentially resolve it.

Bluetooth usb dongle cambridge silicon radio