[Bug 220344] Intel AX211 bluetooth randomly disconnects and reconnects, started after kernel update

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=220344

--- Comment #5 from Tal Licht (tal.lich@gmail.com) ---
Update - unfortunately Bluetooth did start disconnecting, it only took a
bit longer this time. So no improvement even after downgrading the firmware
:(

[ 4945.041226] Bluetooth: hci0: Hardware error 0x0c
[ 4945.055323] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[ 5413.818394] Bluetooth: hci0: Hardware error 0x0c
[ 5413.832258] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[ 6078.608374] Bluetooth: hci0: Hardware error 0x0c
[ 6078.622543] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[ 6154.472547] Bluetooth: hci0: Hardware error 0x0c
[ 6154.486464] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[ 6323.107517] Bluetooth: hci0: Hardware error 0x0c
[ 6323.121611] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[ 9253.552312] Bluetooth: hci0: Hardware error 0x0c
[ 9253.566433] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[10010.348140] Bluetooth: hci0: link tx timeout
[10010.348160] Bluetooth: hci0: killing stalled connection 38:18:4c:be:34:1d
[10371.646448] Bluetooth: hci0: Hardware error 0x0a
[10371.660506] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[10547.126313] Bluetooth: hci0: Hardware error 0x0c
[10547.140440] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[10602.005441] Bluetooth: hci0: Hardware error 0x0a
[10602.019402] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[11660.598378] Bluetooth: hci0: Hardware error 0x0a
[11660.612383] Bluetooth: hci0: Retrieving Intel exception info failed (-16)

On Sun, 20 Jul 2025 at 12:02, Tal Lichtenstein <tal.lich@gmail.com> wrote:

> I've tried going back to the bluetooth firmware that was current at the
> date the computer was originally installed - 9/Sep/2023.
>
> On this date, these firmware files were current:
>
> ibt-0040-0041.sfi - commit 555452997994b250477de4a03b322dc53513d05a dated
> 2023-08-28
> ibt-0040-0041.ddc - commit b7e0c80b00bb4e3d4c845f2270c5c0c8262154ca dated
> 2021-09-15
> iwlwifi-so-a0-gf-a0-86.ucode -
> commit f27dec616e29e44cd90645926c1459639d112c3d dated 2023-11-16 - *this
> is still the current version today*
>
> I switched the files in /lib/firmware to these versions and rebooted:
>
> root@licht-t14s:~# dmesg | grep -E '(hci0|iwlwifi)'
> [   30.809390] iwlwifi 0000:00:14.3: enabling device (0000 -> 0002)
> [   30.830430] iwlwifi 0000:00:14.3: Detected crf-id 0x400410, cnv-id
> 0x80400 wfpm id 0x80000020
> [   30.830491] iwlwifi 0000:00:14.3: PCI dev 51f1/0090, rev=0x370,
> rfid=0x2010d000
> [   30.835929] iwlwifi 0000:00:14.3: TLV_FW_FSEQ_VERSION: FSEQ Version:
> 0.0.2.41
> *[   30.836818] iwlwifi 0000:00:14.3: loaded firmware version
> 86.fb5c9aeb.0 so-a0-gf-a0-86.ucode op_mode iwlmvm*
> [   30.839236] Bluetooth: hci0: Device revision is 0
> [   30.839241] Bluetooth: hci0: Secure boot is enabled
> [   30.839242] Bluetooth: hci0: OTP lock is enabled
> [   30.839243] Bluetooth: hci0: API lock is enabled
> [   30.839244] Bluetooth: hci0: Debug lock is disabled
> [   30.839245] Bluetooth: hci0: Minimum firmware build 1 week 10 2014
> [   30.839246] Bluetooth: hci0: Bootloader timestamp 2019.40 buildtype 1
> build 38
> [   30.840962] Bluetooth: hci0: DSM reset method type: 0x00
> *[   30.844291] Bluetooth: hci0: Found device firmware:
> intel/ibt-0040-0041.sfi*
> [   30.844304] Bluetooth: hci0: Boot Address: 0x100800
> *[   30.844305] Bluetooth: hci0: Firmware Version: 254-28.23*
> [   30.982422] iwlwifi 0000:00:14.3: Detected Intel(R) Wi-Fi 6E AX211
> 160MHz, REV=0x370
> [   31.158040] iwlwifi 0000:00:14.3: WFPM_UMAC_PD_NOTIFICATION: 0x20
> [   31.158093] iwlwifi 0000:00:14.3: WFPM_LMAC2_PD_NOTIFICATION: 0x1f
> [   31.158101] iwlwifi 0000:00:14.3: WFPM_AUTH_KEY_0: 0x90
> [   31.158109] iwlwifi 0000:00:14.3: CNVI_SCU_SEQ_DATA_DW9: 0x0
> [   31.158396] iwlwifi 0000:00:14.3: loaded PNVM version e28bb9d7
> [   31.159564] iwlwifi 0000:00:14.3: RFIm is deactivated, reason = 4
> [   31.174653] iwlwifi 0000:00:14.3: Detected RF GF, rfid=0x2010d000
> [   31.244329] iwlwifi 0000:00:14.3: base HW address: 10:f6:0a:05:ba:09
> [   31.260051] iwlwifi 0000:00:14.3: iwlmvm doesn't allow to disable BT
> Coex, check bt_coex_active module parameter
> [   31.294784] iwlwifi 0000:00:14.3 wlp0s20f3: renamed from wlan0
> [   31.793193] iwlwifi 0000:00:14.3: WFPM_UMAC_PD_NOTIFICATION: 0x20
> [   31.793252] iwlwifi 0000:00:14.3: WFPM_LMAC2_PD_NOTIFICATION: 0x1f
> [   31.793260] iwlwifi 0000:00:14.3: WFPM_AUTH_KEY_0: 0x90
> [   31.793269] iwlwifi 0000:00:14.3: CNVI_SCU_SEQ_DATA_DW9: 0x0
> [   31.794692] iwlwifi 0000:00:14.3: RFIm is deactivated, reason = 4
> [   31.892352] iwlwifi 0000:00:14.3: Registered PHC clock: iwlwifi-PTP,
> with index: 0
> [   32.392539] Bluetooth: hci0: Waiting for firmware download to complete
> [   32.393277] Bluetooth: hci0: Firmware loaded in 1512675 usecs
> [   32.393369] Bluetooth: hci0: Waiting for device to boot
> [   32.409352] Bluetooth: hci0: Device booted in 15680 usecs
> *[   32.409513] Bluetooth: hci0: Found Intel DDC parameters:
> intel/ibt-0040-0041.ddc*
> [   32.412401] Bluetooth: hci0: Applying Intel DDC parameters completed
> *[   32.415476] Bluetooth: hci0: Firmware timestamp 2023.28 buildtype 1
> build 68350*
> [   32.415482] Bluetooth: hci0: Firmware SHA1: 0xc64314a8
> [   32.587297] Bluetooth: hci0: Bad flag given (0x1) vs supported (0x0)
> [   32.587398] Bluetooth: hci0: Bad flag given (0x1) vs supported (0x0)
> [   32.587484] Bluetooth: hci0: Bad flag given (0x1) vs supported (0x0)
> [   32.587627] Bluetooth: hci0: Bad flag given (0x1) vs supported (0x0)
>
> Bluetooth keyboard, mouse and headphones connected automatically. I then
> proceeded to play some music in Spotify which in my experience shortens the
> time until the disconnection issue happens.
>
> Sure enough after less than 1 minute I started hearing bluetooth sound
> hiccups which indicate a problem with the bluetooth connection. These
> repeat occasionally.
> ***However**, *the devices DID NOT disconnect even after 1 hour of
> continuous use and I did not see the error message I did with the newer
> firmware:
>
> kernel: Bluetooth: hci0: Hardware error 0x0c
>
> So this is already some improvement. What I can also try is to downgrade
> the kernel from the HWE version (6.8) to the GA version (5.15) and see if
> that helps. I'll try that later once I have a grip I know what I'm doing :-)
>
>
>
>
> On Sat, 19 Jul 2025 at 16:36, Tal Lichtenstein <tal.lich@gmail.com> wrote:
>
>> I think this is not the same bug as 220341 - that bug reports the stack
>> crashing and Bluetooth becoming disabled. This is not the case here - it
>> just causes devices to disconnect periodically. I suspect the firmware is
>> crashing and restarting but have no way to verify this. I will try however
>> to switch to some older firmware and see if this stops. Will report the
>> results.
>>
>> On Sat, Jul 19, 2025, 15:06 <bugzilla-daemon@kernel.org> wrote:
>>
>>> https://bugzilla.kernel.org/show_bug.cgi?id=220344
>>>
>>> --- Comment #2 from Paul Menzel (
>>> pmenzel+bugzilla.kernel.org@molgen.mpg.de) ---
>>> Was the Linux firmware updated on your system, so you actually need to
>>> test an
>>> *older* firmware version?
>>>
>>> --
>>> You may reply to this email to add a comment.
>>>
>>> You are receiving this mail because:
>>> You reported the bug.
>>
>>

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