| Kernel 5.15 Regression | ' Bluetooth: hci0: command tx timeout '

[Gre0]

With the current daily-build of 'jammy 22.04' it is not possible to enable Bluetooth with (some) Intel Bluetooth devices after reboot/warm boot.
With a Cold boot it is working.

My hardware: $ lsusb
Bus 001 Device 004: ID 8087:0a2a Intel Corp. Bluetooth wireless interface

This is because of a regression in Kernel 5.15 and was present in Fedora and other Distributions as well.
https://bugzilla.redhat.com/show_bug.cgi?id=2027071
https://bugzilla.opensuse.org/show_bug.cgi?id=1193124

For example on Fedora35 my Bluetooth did not initialize correctly
after warm boot between versions 5.14.18 > 5.15.14.
After a cold boot it worked.
(Turned off the desktop PC and disconnected it from power for a few seconds.)

Kernel 5.15.15 changed that and since then everything went fine again.
https://bodhi.fedoraproject.org/updates/FEDORA-2022-a23dd56848

The fix is mentioned there…
https://<email address hidden>/T/#m77ab9e84eec72d1b3e16d6862ffb1a2670277d94

Direct-Link to commit mentioned in the above discussion…
https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/commit/?id=95655456e7cee858a23793f67025765b4c4c227b

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: linux-image-generic-hwe-20.04 5.15.0.18.18
ProcVersionSignature: Ubuntu 5.15.0-18.18-generic 5.15.12
Uname: Linux 5.15.0-18-generic x86_64
ApportVersion: 2.20.11-0ubuntu76
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Fri Feb 4 12:26:46 2022
InstallationDate: Installed on 2022-02-02 (1 days ago)
InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Alpha amd64 (20220201)
MachineType: Gigabyte Technology Co., Ltd. AB350N-Gaming WIFI
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.15.0-18-generic root=UUID=91d2d15b-9614-4498-bb5c-d3376034009f ro quiet splash
RelatedPackageVersions:
 linux-restricted-modules-5.15.0-18-generic N/A
 linux-backports-modules-5.15.0-18-generic N/A
 linux-firmware 20220124.git0c6a7b3b-0ubuntu1
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/13/2021
dmi.bios.release: 5.17
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: F51d
dmi.board.asset.tag: Default string
dmi.board.name: AB350N-Gaming WIFI-CF
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: Default string
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInternational,LLC.:bvrF51d:bd12/13/2021:br5.17:svnGigabyteTechnologyCo.,Ltd.:pnAB350N-GamingWIFI:pvrDefaultstring:rvnGigabyteTechnologyCo.,Ltd.:rnAB350N-GamingWIFI-CF:rvrDefaultstring:cvnDefaultstring:ct3:cvrDefaultstring:skuDefaultstring:
dmi.product.family: Default string
dmi.product.name: AB350N-Gaming WIFI
dmi.product.sku: Default string
dmi.product.version: Default string
dmi.sys.vendor: Gigabyte Technology Co., Ltd.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Gre0 (gre0)]

The bug does not seem to be present anymore.
After a reboot, Bluetooth is working.

(Kernel: 5.15.0-23-generic)

[Andrey Kudinov (elhana)]

Bug still present:
$ uname -r
5.19.0-29-generic

lsusb |grep Bluetooth
Bus 003 Device 002: ID 8087:0029 Intel Corp. AX200 Bluetooth

Upstream bug and patch that seems to fix it for me:
https://bugzilla.kernel.org/show_bug.cgi?id=215167#c38

[Chaim Eliyah (chaimeliyah)]

Yes.. I'm a little confused. For example the previously mentioned thread (id=215167) is still very much ongoing, with some people reporting that certain kernel versions fix this and others reporting it showing up in regressions as late as 6.2.

They referenced a message https://<email address hidden>/ refers to commit 95655456e7cee858a23793f67025765b4c4c227b upstream, which was merged into 5.16 mainline last year. https://lkml.org/lkml/2022/1/14/195 -- I will post back in the bugzilla thread later that this seems to be unrelated.

I believe on the Ubuntu side patching from 5.11 to 5.15 caused this problem for me. And it would appear that 5.19 has it as well. But needless to say in "stable LTS" (22.04.2/5.15) this is still happening, breaking bluetooth for Ubuntu users.

[Chaim Eliyah (chaimeliyah)]

Not a huge fan of copy-pasta but this may be more useful here.

+1 AX200

```
07:00.0 Network controller [0280]: Intel Corporation Wi-Fi 6 AX200 [8086:2723] (rev 1a)
 Subsystem: Intel Corporation Wi-Fi 6 AX200NGW [8086:0084]
 Kernel driver in use: iwlwifi
 Kernel modules: iwlwifi
```

```
[ 25.711840] Bluetooth: Core ver 2.22
[ 25.711860] NET: Registered PF_BLUETOOTH protocol family
[ 25.711861] Bluetooth: HCI device and connection manager initialized
[ 25.711864] Bluetooth: HCI socket layer initialized
[ 25.711866] Bluetooth: L2CAP socket layer initialized
[ 25.711869] Bluetooth: SCO socket layer initialized
[ 25.788390] iwlwifi 0000:07:00.0: loaded firmware version 66.f1c864e0.0 cc-a0-66.ucode op_mode iwlmvm
[ 27.783372] Bluetooth: hci0: command 0xfc05 tx timeout
[ 27.783378] Bluetooth: hci0: Reading Intel version command failed (-110)
[ 28.785728] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 28.785731] Bluetooth: BNEP filters: protocol multicast
[ 28.785733] Bluetooth: BNEP socket layer initialized
```

```
celiyah@darkunicorn:~$ sudo systemctl status bluetooth
● bluetooth.service - Bluetooth service
     Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
     Active: active (running) since Sun 2023-02-26 16:43:43 CST; 12min ago
       Docs: man:bluetoothd(8)
   Main PID: 28973 (bluetoothd)
     Status: "Running"
      Tasks: 1 (limit: 76959)
     Memory: 668.0K
        CPU: 38ms
     CGroup: /system.slice/bluetooth.service
             └─28973 /usr/lib/bluetooth/bluetoothd

```

```
celiyah@darkunicorn:~$ bluetoothctl
Agent registered
[bluetooth]# scan on
No default controller available
quitetooth]#
```

It's popping up in Ubuntu forums e.g.
https://askubuntu.com/questions/1448731/bluetooth-not-working-no-controller-available

| Reloading `btusb` module several times makes it working.

Any specific steps for this? I have not been able to get it to work. Issue persists despite reboots incl. hard power off/on. This happened suddenly.

```
celiyah@darkunicorn:~$ uname -a
Linux darkunicorn 5.15.0-56-lowlatency #62-Ubuntu SMP PREEMPT Wed Nov 23 09:50:07 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
celiyah@darkunicorn:~$ lsmod | grep bt
btusb 61440 0
btrtl 24576 1 btusb
btbcm 24576 1 btusb
btintel 40960 1 btusb
bluetooth 708608 12 btrtl,btintel,btbcm,bnep,btusb
```

(I believe the bleeding cutting edge 23.04.1 is the only available bunty release with a 6 kernel line. Could be wrong.)

Note the workaround in the askubuntu question: https://askubuntu.com/a/1456898/253482 (for transparency, I'm linking to my own answer).