Public bug reported:
Bluetooth RTL8723BE not discovering devices on Kubuntu 26.04 (kernel
7.0.0-34)
HARDWARE
Laptop with M.2 Key E combo adapter, Realtek RTL8723BE:
- WiFi: Realtek RTL8723BE PCIe at 06:00.0 (driver rtl8723be) - WORKS
- Bluetooth: internal USB, ID 0930:0222 "Toshiba Corp. Bluetooth Radio" (driver
btusb + btrtl) - DOES NOT WORK
- USB path: 2-11, behind Intel USB controller (pci 00:14.0)
SOFTWARE
- OS: Kubuntu 26.04.1 LTS
- Kernel: 7.0.0-34-generic #34-Ubuntu SMP PREEMPT_DYNAMIC
- bluez: 5.85-4ubuntu0.2
- btusb version: 0.8
- linux-firmware: 20260319.git217ca6e4.1ubuntu
SYMPTOM
The adapter is detected, btusb binds correctly to both interfaces, hci0 reaches
UP RUNNING INQUIRY, and it transmits 163 HCI commands. But it never receives a
single reply. Scanning always returns 0 devices.
Works normally on Windows and on Debian 13 (kernel 6.12). This is Ubuntu 26.04
with kernel 7.0.0 only.
DRIVER BINDING IS CORRECT
2-11:1.0 -> btusb
2-11:1.1 -> btusb
bInterfaceClass/SubClass/Protocol = e0/01/01 (Bluetooth)
btusb alias present: usb:v0930p*d*dc*dsc*dp*icFFisc01ip01in*
HCI STATE
hci0: Type: Primary Bus: USB
BD Address: C8:FF:28:BA:03:F9 ACL MTU: 820:8 SCO MTU: 255:16
UP RUNNING INQUIRY
RX bytes:1870 acl:0 sco:0 events:197 errors:0
TX bytes:6906 acl:0 sco:0 commands:163 errors:0
KERNEL ERRORS
Bluetooth: hci0: urb 00000000019bd5c1 failed to resubmit (2)
bluetoothd[1238]: Failed to set mode: Failed (0x03)
HCI TRACE (btmon)
Commands go out and get Command Complete, but no responses ever come back:
< HCI Command: Inquiry (0x01|0x0001)
> HCI Event: Command Status (0x0f)
< HCI Command: LE Set Scan Enable (0x08|0x000c)
> HCI Event: Command Complete (0x0e)
Response events observed: 0
Inquiry Result: 0
LE Advertising Report: 0
Remote Name Complete: 0
Connection Complete: 0
The controller acknowledges every command but the radio never responds.
HCI ERROR 0x03 = "Hardware General Error" on every boot at bluetoothd
startup.
WHAT WAS RULED OUT
- rfkill soft block: resolved (rfkill unblock + persistent systemd unit), no
change
- USB autosuspend (2000 ms): resolved (power/control=on + udev rule), no change
- HCI reset via modprobe -r btusb / modprobe btusb: no change
- USB unbind/bind on port 2-11: leaves chip without BD Address
(00:00:00:00:00:00),
only recovers on cold boot
- Cold boot: restores BD Address correctly, still 0 devices found
- Regulatory domain set to AR: no change
- Kernel 7.0.0-30: same btusb 0.8 driver, same failure
- Kernel 6.12.107+deb13-amd64 (Debian 13 kernel, where BT works): does not boot
in Ubuntu (manually installed .deb, dependency mismatch)
ADDITIONAL CONTEXT
- WiFi half of the same combo card works fine (rtl8723be, firmware
rtlwifi/rtl8723befw_36.bin)
- Chip reports LMP Version 4.0, Subversion 0x8723, Manufacturer Realtek
- linux-firmware contains rtl8723b_config-OBDA8723.bin
QUESTIONS
1. Is there a known regression in btusb or the USB firmware path in kernel 7.0.x
affecting Realtek RTL8723B composite devices, where the radio enters a zombie
state after HCI error 0x03 and never recovers?
2. Does the Bluetooth half of the RTL8723BE require a specific firmware blob
that Debian loads but Ubuntu does not?
3. Is USB unbind/bind not being sufficient to reset the controller, and is a
cold boot or a different reset procedure required?
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2169036
Title:
Bluetooth RTL8723BE (USB 0930:0222) never discovers any devices on
26.04 (kernel 7.0.0-34)
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