[Bug 217812] New: Bluetooth: hci0: unexpected cc 0x041a length: 7 > 1 on bluetooth scan (CSR chip)

[Bug 217812] New: Bluetooth: hci0: unexpected cc 0x041a length: 7 > 1 on bluetooth scan (CSR chip)

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=217812

            Bug ID: 217812
           Summary: Bluetooth: hci0: unexpected cc 0x041a length: 7 > 1 on
                    bluetooth scan (CSR chip)
           Product: Drivers
           Version: 2.5
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P3
         Component: Bluetooth
          Assignee: linux-bluetooth@vger.kernel.org
          Reporter: georg.schwarz@freenet.de
        Regression: No

The bug occurs with the following USB bluetooth dongle:

https://fccid.io/SHP-BED009/Label/Label-Location-and-Sample-572556

USB ID 0x0a12 0x0001

identified by the kernel as

Bluetooth: hci0: CSR: Setting up dongle with HCI ver=3 rev=07a6; LMP ver=3
subver= 07a6; manufacturer=10

I opened up the dongle, and the chip has a CSR logo and the following
inscription printed on it: 41B14 3A05U 549AE

I know that 0x0a12 0x0001 are often fake Chinese chips, but this one to the
best of my knowledge is an original one (BT 2.0).
(and the kernel correctly does not identify it as a fake, so that's not the
issue here).


Description of the bug:
When scanning for bluetooth devices (using Blueman's Search) any bluetooth
device (e.g. phone, speaker, etc.) found is listed with its MAC only, not its
name, unless that device has previously been paired with (and its data is
cached in /var/lib/bluetooth/(adapter's MAC)/cache/, in which case the name is
probably not queried).
In the system log the following entry is added on every search which yields at
least one such "MAC-only" device:

Bluetooth: hci0: unexpected cc 0x041a length: 7 > 1

Needless to say the devices' names do resolve when scanned from other
computers/phones (including from another Linux system running the same fresh
Manjaro installation but featuring different BT hardware).

I have tested it on two different machines (with the above BT dongle) with
numerous Linux distributions and kernels and bluez releases. I can reproduce it
directly with a Manjaro or Xubuntu live/install image.
The above kernel message occurs with kernels 6.1.44, 6.4.9 and 6.5.0rc5.

None of the test machines are dual-boot, they are Linux-only.

With some much older installations (Xubuntu 16 or 18 for example), the BT names
do not get resolved either (same behavior), but the syslog message is a
different one:

Bluetooth: hci0: last event is not cmd complete (0x0f)

I suspect that it is still the same bug though, just a different message in
older kernels.

In addition, I noticed the following which may or may not be related:
When booting up without the BT dongle attached and then plugging it in, the
following message is written to syslog (before the kernel messages about the
new BT device):

Bluetooth: hci0: unexpected event for opcode 0x0000

This is true for all the kernels I tried (at least the 6.X ones).

I initially opened an issue with Blueman
(https://github.com/blueman-project/blueman/issues/2116), but I am convinced
now that it is actually a driver (kernel) issue.

If I can provide further information or tests, please kindly let me know.
Thanks.

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