I have an ASUS USB Bluetooth Controller. It worked fine in the past, but after an update today it stopped working (admittedly, I don't know if the update caused it or not; I hadn't used bluetooth in a week or two). I can toggle bluetooth on in Settings. However, nothing happens. If I switch tabs and come back to bluetooth, it will be off again. Bluetooth Manager spins for a while but never opens. bluetoothctl says there is no default controller, and list prints nothing.
I tried it in Windows, and it worked fine. I was able to connect a controller. So the USB adapter clearly works fine. It's something with Ubuntu. Per this question, I tried running sudo rmmod btusb and sudo modprobe btusb, but nothing changed.
Running Ubuntu 20.04 with kernel release 5.13.0-28-generic. MSI B550 Tomahawk Motherboard.
lsusb recognizes that the USB adapter exists. But bluetoothctl does not. lsusb -v output:
Bus 001 Device 004: ID 0b05:190e ASUSTek Computer, Inc. ASUS USB-BT500
Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 224 Wireless bDeviceSubClass 1 Radio Frequency bDeviceProtocol 1 Bluetooth bMaxPacketSize0 64 idVendor 0x0b05 ASUSTek Computer, Inc. idProduct 0x190e bcdDevice 2.00 iManufacturer 1 iProduct 2 iSerial 3 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x00b1 bNumInterfaces 2 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xe0 Self Powered Remote Wakeup MaxPower 500mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 3 bInterfaceClass 224 Wireless bInterfaceSubClass 1 Radio Frequency bInterfaceProtocol 1 Bluetooth iInterface 4 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0010 1x 16 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 0 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 224 Wireless bInterfaceSubClass 1 Radio Frequency bInterfaceProtocol 1 Bluetooth iInterface 4 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x03 EP 3 OUT bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0000 1x 0 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x83 EP 3 IN bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0000 1x 0 bytes bInterval 1 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 1 bNumEndpoints 2 bInterfaceClass 224 Wireless bInterfaceSubClass 1 Radio Frequency bInterfaceProtocol 1 Bluetooth iInterface 4 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x03 EP 3 OUT bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0009 1x 9 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x83 EP 3 IN bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0009 1x 9 bytes bInterval 1 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 2 bNumEndpoints 2 bInterfaceClass 224 Wireless bInterfaceSubClass 1 Radio Frequency bInterfaceProtocol 1 Bluetooth iInterface 4 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x03 EP 3 OUT bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0011 1x 17 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x83 EP 3 IN bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0011 1x 17 bytes bInterval 1 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 3 bNumEndpoints 2 bInterfaceClass 224 Wireless bInterfaceSubClass 1 Radio Frequency bInterfaceProtocol 1 Bluetooth iInterface 4 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x03 EP 3 OUT bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0019 1x 25 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x83 EP 3 IN bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0019 1x 25 bytes bInterval 1 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 4 bNumEndpoints 2 bInterfaceClass 224 Wireless bInterfaceSubClass 1 Radio Frequency bInterfaceProtocol 1 Bluetooth iInterface 4 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x03 EP 3 OUT bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0021 1x 33 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x83 EP 3 IN bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0021 1x 33 bytes bInterval 1 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 5 bNumEndpoints 2 bInterfaceClass 224 Wireless bInterfaceSubClass 1 Radio Frequency bInterfaceProtocol 1 Bluetooth iInterface 4 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x03 EP 3 OUT bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0031 1x 49 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x83 EP 3 IN bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0031 1x 49 bytes bInterval 11 Answer
I had a similar situation. I had previously installed fetched and installed ASUS drivers, but it stopped working. Runninghciconfig -a; dmesg | egrep -i 'blue|firm' gave:
[ 870.934814] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761b_fw.bin
[ 870.934838] bluetooth hci0: Direct firmware load for rtl_bt/rtl8761b_fw.bin failed with error -2
[ 870.934841] Bluetooth: hci0: RTL: firmware file rtl_bt/rtl8761b_fw.bin not foundSolved it by reinstalling the "ASUS USB-BT500 Driver 1.0.0.8 for Linux" (link) with the following two commands: sudo make install INTERFACE=usb and restarting bluetooth with sudo systemctl restart bluetooth. I had to unplug and reinsert bluetooth adapter for it to work last time.
