Not Searching devices and also Not Discoverable by other devices

[WaheedAbbas]

blueman: 2.3.4 BlueZ: 5.64-0ubuntu1 Distribution: LinuxMint 21.1 Desktop environment: XFCE Kernel: 5.15.0-56-generic

• [x] I have consulted the Troubleshooting page and done my best effort to follow.

  I have a Ugreen Bluetooth 5.0 Adapter with chip RTL8761BUV. Blueman is able to detect it but does not search any devices and is also not discoverable by other devices.

  Things I have tried so far are: 1) Patch Kernal with { USB_DEVICE(0x2b89, 0x8761), .driver_info = BTUSB_REALTEK }, but that just fully kills it and is not able to detect the controller anymore so I had to revert the changes. 2) Uncheck "Hide Unnamed devices" 3) rfkill unblock 4) Place /lib/firmware/rtl_bt/rtl8761b_fw.bin and /lib/firmware/rtl_bt/rtl8761b_config.bin files in /lib/firmware/rtl_bt/ 5) Tried Ubuntu 22.10; same result

  This is the result of sudo dmesg | grep -i bluetooth and hciconfig -a

[cschramm]

The firmware should already be in place from the linux-firmware package and I'd clearly expect the btrtl driver to jump in. Did you try modprobeing it explicitly?

[cschramm]

Patch Kernal with { USB_DEVICE(0x2b89, 0x8761), .driver_info = BTUSB_REALTEK }

Ah yeah. If that's the correct ID, that entry seems necessary as it just recently got added to Linux 6.2-rc1.

[WaheedAbbas]

I am not sure how to execute the modprobe command. I ran modprobe rtl8761b, it showed "Module rtl8761b not found in directory /lib/modules/5.15.0-56-generic". But if I patch Kernel, Blueman no longer detects the controller and shows "no default controller available". Running the list command doesn't show any controller either. lsusb shows "2b89:8761 Realtek Bluetooth Radio", so I believe PID and VID are correct.

[infirit]

It may be failing to load the firmware, see https://bugs.launchpad.net/ubuntu/+source/linux-firmware/+bug/1968604

[cschramm]

The module is btrtl, but the way forward is patching in the device and checking what happens with dmesg. The bug mentioned by @infirit sounds like Ubuntu or Linux in general gets something wrong with UART vs. USB firmware for that chip, so that linking to the rtl8761b files (that should be the UART firmware) from the rtl8761bu files (that should be the USB firmware) seems to help in some cases. :shrug:

[WaheedAbbas]

Thank you. That worked. What I did was: 1) Patch Kernel with { USB_DEVICE(0x2b89, 0x8761), .driver_info = BTUSB_REALTEK | BTUSB_WIDEBAND_SPEECH },. It stopped recognizing the adapter as before but I didn't panic. 2) I installed drivers for RTL8761b 3) Ran cd /usr/lib/firmware/rtl_bt and sudo ln -s rtl8761b_fw.bin rtl8761bu_fw.bin 4) Reboot: Super Important

[cschramm]

Just for the record: You should not need external drivers and that repository looks out of date. The linux-firmware package ships both rtl8761b and rtl8761bu (and it looks like there are situations where you need to provide its b as bu for things to work).