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Date: Fri, 7 Jun 2024 08:10:09 +0200
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Subject: Re: Bluetooth Kernel Bug: After connecting either HFP/HSP or A2DP is
 not available (Regression in 6.9.3, 6.8.12)
To: Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
 =?UTF-8?Q?Timo_Schr=C3=B6der?= <der.timosch@gmail.com>
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From: "Linux regression tracking (Thorsten Leemhuis)"
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On 06.06.24 23:23, Luiz Augusto von Dentz wrote:
> On Thu, Jun 6, 2024 at 4:46 PM Timo Schröder <der.timosch@gmail.com> wrote:
>> on my two notebooks, one with Ubuntu (Mainline Kernel 6.9.3, bluez
>> 5.7.2) and the other one with Manjaro (6.9.3, bluez 5.7.6) I'm having
>> problems with my Sony WH-1000XM3 and Shure BT1. Either A2DP or HFP/HSP
>> is not available after the connection has been established after a
>> reboot or a reconnection. It's reproducible that with the WH-1000XM3
>> the A2DP profiles are missing and with the Shure BT1 HFP/HSP profiles
>> are missing. It also takes longer than usual to connect and I have a
>> log message in the journal:
>>
>> Jun 06 16:28:10 liebig bluetoothd[854]:
>> profiles/audio/avdtp.c:cancel_request() Discover: Connection timed out
>> (110)
>>
>> When I disable and re-enable bluetooth (while the Headsets are still
>> on) and trigger a reconnect from the notebooks, A2DP and HFP/HSP
>> Profiles are available again.
>>
>> I also tested it with 6.8.12 and it's the same problem. 6.8.11 and
>> 6.9.2 don't have the problem.
>> So I did a bisection. After reverting commit
>> af1d425b6dc67cd67809f835dd7afb6be4d43e03 "Bluetooth: HCI: Remove
>> HCI_AMP support" for 6.9.3 it's working again without problems.
>>
>> Let me know if you need anything from me.
> 
> Wait what, that patch has nothing to do with any of these profiles not
> really sure how that would cause a regression really, are you sure you
> don't have actual connection timeout happening at the link layer and
> that by some chance didn't happen when running with HCI_AMP reverted?
> 
> I'd be surprised that HCI_AMP has any effect in most controllers
> anyway, only virtual controllers was using that afaik.

Stupid question from a bystander without knowledge in the field (so feel
free to ignore this): is that patch maybe causing trouble because it has
some hidden dependency on a earlier change that was not backported to
6.9.y?

Timo, to rule that out (and it's good to know in general, too) it would
be good to known if current mainline (e.g. 6.10-rc) is affected as well.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
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