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New: Bluetooth (RTL8852BU, 0bda:b853) never initializes. Opcode 0xfcf0

Bug 221837 [email protected] 1 participant 12 messages Aug 5 – Aug 31 Bluetooth drivers

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#0 lore raw

https://bugzilla.kernel.org/show_bug.cgi?id=221837

            Bug ID: 221837
           Summary: Bluetooth (RTL8852BU, 0bda:b853) never initializes.
                    Opcode 0xfcf0
           Product: Drivers
           Version: 2.5
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: blocking
          Priority: P3
         Component: Bluetooth
          Assignee: [email protected]
          Reporter: [email protected]
        Regression: No

## System information
- Distro: Linux Mint 22.3 (zena), Ubuntu 24.04 base
- Kernel: 6.11.0-17-generic (#17~24.04.2-Ubuntu SMP PREEMPT_DYNAMIC)
- linux-firmware package: 20240318.git3b128b60-0ubuntu2.27
- Laptop: Lenovo LOQ 15AHP11
- Bluetooth controller: Realtek RTL8852BU, USB ID 0bda:b853 (Bus 001 Device
004)
- WiFi: Realtek RTL8852BE, PCI ID 10ec:b852, driver rtw89_8852be

## Problem
hci0 never comes up. BD Address stays 00:00:00:00:00:00, state DOWN, bluetoothctl show reports "No default controller available". Reproduces on every boot.

## dmesg (current state, after updating rtl8852bu_fw.bin)

```
[    2.491778] Bluetooth: hci0: RTL: examining hci_ver=0b hci_rev=000b
lmp_ver=0b lmp_subver=8852
[    2.494811] Bluetooth: hci0: RTL: rom_version status=0 version=3
[    2.494818] Bluetooth: hci0: RTL: loading rtl_bt/rtl8852bu_fw.bin
[    2.495778] Bluetooth: hci0: RTL: loading rtl_bt/rtl8852bu_config.bin
[    2.503791] Bluetooth: hci0: Opcode 0xfcf0 failed: -16
[    2.507788] Bluetooth: hci0: AOSP extensions version v0.96
[    2.507793] Bluetooth: hci0: AOSP quality report is not supported
```

## What I've tried

1. Confirmed rfkill is not blocking (Soft blocked: no, Hard blocked: no for both ideapad_bluetooth and hci0).
2. Confirmed Bluetooth works fine from Windows on the same physical hardware (dual-boot). (fast-boot is disabled)
3. The distro-packaged rtl8852bu_fw.bin (linux-firmware 20240318 snapshot) additionally logged Bluetooth: hci0: RTL: didn't find patch for chip id 3 before the Opcode failure i.e. this chip's rom_version (2, reported as "chip id 3") had no matching entry in that firmware build's internal patch table.
4. Replaced /usr/lib/firmware/rtl_bt/rtl8852bu_fw.bin with the current upstream linux-firmware HEAD build (fetched from git.kernel.org, 129733 bytes, md5 c97273d1bf9a715c46e4fc73eb0283b3, valid RTBTCore header). This resolved the "didn't find patch" message but Opcode 0xfcf0 failed: -16 still occurs immediately after.
5. Confirmed via linux-firmware's WHENCE manifest that rtl_bt/rtl8852bu_config.bin -> rtl8761bu_config.bin is the correct, intentional upstream mapping — ruled out using the wrong config file.
6. Full reboot
7. Attempted to isolate a WiFi/Bluetooth coexistence conflict (RTL8852B is a combo WiFi+BT chip) by unloading the rtw89 WiFi stack before reloading btusb. rtw89_8852be/rtw89_8852b/rtw89_8852b_common unloaded, but rtw89_pci/rtw89_core stayed loaded (rmmod dependency-order limitation).
8. Set usbcore.autosuspend=-1 as a kernel boot parameter.

The firmware's patch table now recognizes this chip's rom_version, but the controller still returns "Command Disallowed" on the vendor download-config opcode 0xfcf0. This looks like it needs additional handling in btrtl.c/btusb.c for this specific RTL8852BU chip stepping (rom_version=2). Is there a known driver-side fix in progress, or would a btmon/HCI trace help narrow this down further?

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#1 lore raw

[Bug 221837] Bluetooth (RTL8852BU, 0bda:b853) never initializes. Opcode 0xfcf0

https://bugzilla.kernel.org/show_bug.cgi?id=221837

Artem S. Tashkinov ([email protected]) changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |NEEDINFO

--- Comment #1 from Artem S. Tashkinov ([email protected]) --- This kernel release is not supported.

Can you reproduce the issue using 7.1.6 or 7.2-rc6 **with** the latest firmware?

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#2 lore raw

[Bug 221837] Bluetooth (RTL8852BU, 0bda:b853) never initializes. Opcode 0xfcf0

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=221837

--- Comment #2 from Rohan ([email protected]) ---
Sorry, I forgot to mention that I originally faced this issue in kernel 7.0.0-28 with the the latest firmware. I then tried to jump onto different old kernel versions to see if that might fix the issue. No help. I'm not sure if Mint supports 7.1.6 yet as I cannot see it in Update Manager. I get the same dmesg on the new updated kernel as well:

```
[    1.457364] usb 1-5: Product: Bluetooth Radio
[    2.820216] Bluetooth: Core ver 2.22
[    2.834484] NET: Registered PF_BLUETOOTH protocol family
[    2.834492] Bluetooth: HCI device and connection manager initialized
[    2.834506] Bluetooth: HCI socket layer initialized
[    2.834511] Bluetooth: L2CAP socket layer initialized
[    2.834525] Bluetooth: SCO socket layer initialized
[    2.943691] Bluetooth: hci0: RTL: examining hci_ver=0b hci_rev=000b
lmp_ver=0b lmp_subver=8852
[    2.946667] Bluetooth: hci0: RTL: rom_version status=0 version=3
[    2.949812] Bluetooth: hci0: RTL: btrtl_initialize: key id 0
[    2.949823] Bluetooth: hci0: RTL: loading rtl_bt/rtl8852bu_fw.bin
[    2.950664] Bluetooth: hci0: RTL: loading rtl_bt/rtl8852bu_config.bin
[    2.959682] Bluetooth: hci0: AOSP extensions version v0.96
[    2.959687] Bluetooth: hci0: AOSP quality report is not supported
[    4.661628] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[    4.661634] Bluetooth: BNEP filters: protocol multicast
[    4.661639] Bluetooth: BNEP socket layer initialized
```

Is there anything else I can do?

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#3 lore raw

[Bug 221837] Bluetooth (RTL8852BU, 0bda:b853) never initializes. Opcode 0xfcf0

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=221837

--- Comment #3 from Artem S. Tashkinov ([email protected]) --- Your last log indiciates that your BT adapater is fully functional.

What's the output of sudo bluetoothctl show ?

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#6 lore raw

[Bug 221837] Bluetooth (RTL8852BU, 0bda:b853) never initializes. Opcode 0xfcf0

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=221837

--- Comment #6 from Rohan ([email protected]) ---
As I mentioned earlier, I don't have bluetooth or any other device blocked in rfkill. You can still check the output:

```
1: ideapad_wlan: Wireless LAN
        Soft blocked: no
        Hard blocked: no
2: ideapad_bluetooth: Bluetooth
        Soft blocked: no
        Hard blocked: no
3: phy0: Wireless LAN
        Soft blocked: no
        Hard blocked: no
4: hci0: Bluetooth
        Soft blocked: no
        Hard blocked: no
```
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#8 lore raw

[Bug 221837] Bluetooth (RTL8852BU, 0bda:b853) never initializes. Opcode 0xfcf0

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=221837

Paul Menzel ([email protected]) changed:

What |Removed |Added
----------------------------------------------------------------------------

                 CC|                            |pmenzel+bugzilla.kernel.org
                   |                            |@molgen.mpg.de

--- Comment #8 from Paul Menzel ([email protected]) ---

Quoted 1 line

Hello, any updates? I'm still unable to use bluetooth. Thanks!

If you have any expectations on support times, then please contact the company/entity you contracted to give you support. Otherwise be patient for volunteers to have time to tend to your issue.

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#9 lore raw

[Bug 221837] Bluetooth (RTL8852BU, 0bda:b853) never initializes. Opcode 0xfcf0

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=221837

--- Comment #9 from Paul Menzel ([email protected]) --- Is
https://lore.kernel.org/all/jy7Oxm13JtZE-cHnVc2A83BwwJcviMvaLSDfdHqIlEysqO88jvDwRkqAOqSNaNc66DJdPgQBoWanzce8h-_Mz4kYCe5SYfIafU1tyxN2_dg=@protonmail.ch/
related to your issue?

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#10 lore raw

[Bug 221837] Bluetooth (RTL8852BU, 0bda:b853) never initializes. Opcode 0xfcf0

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=221837

--- Comment #10 from Rohan ([email protected]) ---
I'm sorry I'm not that familiar with Kernel lingo but from what I understood, I think the issue may be related as our Laptop model/specifications and the controller reports are identical. I even checked out other forums in the meantime and it seems like its an actual unsolved problem. Could you please tell if the patch is around the corner?

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