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

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

[bugzilla-daemon]

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

            Bug ID: 220344
           Summary: Intel AX211 bluetooth randomly disconnects and
                    reconnects, started after kernel update
           Product: Drivers
           Version: 2.5
          Hardware: Intel
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P3
         Component: Bluetooth
          Assignee: linux-bluetooth@vger.kernel.org
          Reporter: tal.lich@gmail.com
        Regression: No

Bluetooth devices disconnect every few minutes. Tried same devices with another
laptop with same hardware but Windows OS - works fine. So this is not the
devices or the Bluetooth hardware.

Every time the disconnect happens, dmesg shows:

Jul 16 13:47:24 licht-t14s kernel: Bluetooth: hci0: Retrieving Intel exception
info failed (-16)
Jul 16 13:47:24 licht-t14s kernel: Bluetooth: hci0: Hardware error 0x0c

I have tried:
- Downloading the newest firmware file from linux-firmware (file
ibt-0040-0041.{sfi/ddc}

- Setting the following options in /etc/modprobe.d

# Disable power saving in both iwlmvm and iwlwifi
options iwlmvm power_scheme=1
options iwlwifi power_save=0

# Disable bluetooth coexistence to avoid BT issues
options iwlwifi bt_coex_active=0

I have read on Ubuntu's forum (here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2051720) that this may be
a regression in kernel 6.5 but I'm on a newer kernel

Hardware info:
System  : Lenovo Thinkpad T14s Gen4 model 21F60051IV
BIOS    : N3PET23W (1.14)
Adapter : Intel AX211
Firmware: 133-20.25

OS info:
Kernel  : Linux licht-t14s 6.8.0-60-generic #63~22.04.1-Ubuntu SMP
PREEMPT_DYNAMIC Tue Apr 22 19:00:15 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
Distro  : Ubuntu 22.04.05

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

[bugzilla-daemon]

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

Paul Menzel (pmenzel+bugzilla.kernel.org@molgen.mpg.de) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pmenzel+bugzilla.kernel.org
                   |                            |@molgen.mpg.de

--- Comment #1 from Paul Menzel (pmenzel+bugzilla.kernel.org@molgen.mpg.de) ---
Thank you for your report. Is this a duplicate of bug 220341 ([URL][1])?

If yes, and you ruled out the newer firmware, than bisecting the issue is
needed. As it’s not immediately reproducible this might take some time though.

[1]: https://bugzilla.kernel.org/show_bug.cgi?id=220341

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

[bugzilla-daemon]

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?

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

[bugzilla-daemon]

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

--- Comment #3 from Tal Licht (tal.lich@gmail.com) ---
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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[Bug 220344] Intel AX211 bluetooth randomly disconnects and reconnects, started after kernel update

[bugzilla-daemon]

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

--- Comment #4 from Tal Licht (tal.lich@gmail.com) ---
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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[Bug 220344] Intel AX211 bluetooth randomly disconnects and reconnects, started after kernel update

[bugzilla-daemon]

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

[bugzilla-daemon]

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

--- Comment #6 from Tal Licht (tal.lich@gmail.com) ---
I've also tried downgrading to the GA kernel (5.15).
When I boot this the Wifi driver (iwlwifi) doesn't even load and my
external USB-C monitor does not initialize at all.
So using this is not an option :-)


On Sun, 20 Jul 2025 at 14:30, Tal Lichtenstein <tal.lich@gmail.com> wrote:

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

[bugzilla-daemon]

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

Juerg Haefliger (juergh@proton.me) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |juergh@proton.me

--- Comment #7 from Juerg Haefliger (juergh@proton.me) ---
This looks like:
https://bugs.launchpad.net/bugs/2049676

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

[bugzilla-daemon]

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

Guy Rutenberg (guyrutenberg@gmail.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |guyrutenberg@gmail.com

--- Comment #8 from Guy Rutenberg (guyrutenberg@gmail.com) ---
Hi,

I have the exact same issue on similar hardware - Lenovo T14 Gen4. It started a
while ago (more than a year). The issue manifests itself only in certain
locations: The same computer and bluetooth headset work perfectly fine in my
office, but I get the hiccups and disconnects at home.

I've already tried everything Tal wrote down as well. I've tried various
kernels and downgraded the iwlwifi firmware all the way back to Dec 2022 and
couldn't find the version it worked properly with.

I'm running kernel 6.18.15+deb14-amd64, Debian Unstable.

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