Re: [REGRESSION] Bluetooth is not working on Macs with BCM4377 chip starting from kernel 6.5
From: Aditya Garg
Date: Tue Nov 21 2023 - 06:42:42 EST
> On 20-Nov-2023, at 4:37 PM, Hector Martin <marcan@xxxxxxxxx> wrote:
>
>
>
>> On 2023/11/19 4:31, Aditya Garg wrote:
>>
>>
>>>> On 14-Nov-2023, at 3:14 PM, Hector Martin <marcan@xxxxxxxxx> wrote:
>>>
>>> On 14/11/2023 18.03, Aditya Garg wrote:
>>>>
>>>>
>>>>> On 14-Nov-2023, at 1:28 PM, Hector Martin <marcan@xxxxxxxxx> wrote:
>>>>>
>>>>> On 14/11/2023 15.59, Hector Martin wrote:
>>>>>> On 14/11/2023 15.23, Aditya Garg wrote:
>>>>>>>
>>>>>>>
>>>>>>>> On 14-Nov-2023, at 5:01 AM, Bagas Sanjaya <bagasdotme@xxxxxxxxx> wrote:
>>>>>>>>
>>>>>>>> On Mon, Nov 13, 2023 at 08:57:35PM +0000, Aditya Garg wrote:
>>>>>>>>> Starting from kernel 6.5, a regression in the kernel is causing Bluetooth to not work on T2 Macs with BCM4377 chip.
>>>>>>>>>
>>>>>>>>> Journalctl of kernel 6.4.8 which has Bluetooth working is given here: https://pastebin.com/u9U3kbFJ
>>>>>>>>>
>>>>>>>>> Journalctl of kernel 6.5.2, which has Bluetooth broken is given here: https://pastebin.com/aVHNFMRs
>>>>>>>>>
>>>>>>>>> Also, the bug hasn’t been fixed even in 6.6.1, as reported by users.
>>>>>>>>
>>>>>>>> Can you bisect this regression please?
>>>>>>>
>>>>>>> Since I don't have access to this hardware, it's not possible for me to bisect this regression. Let's hope someone is able to do so though.
>>>>>>
>>>>>> It's not a regression, it was always broken. I'm sending a patch.
>>>>>>
>>>>>> - Hector
>>>>>
>>>>> You are quite likely conflating two problems. The ubsan issue you quoted
>>>>> was always there and the patch I just sent fixes it, but it almost
>>>>> certainly always worked fine in practice without ubsan.
>>>>>
>>>>> The Bluetooth problem you are referring to is likely *specific to
>>>>> Bluetooth LE devices* and the regression was introduced by 288c90224e
>>>>> and fixed by 41e9cdea9c, which is also in 6.5.11 and 6.6.1.
>>>>>
>>>>> If Bluetooth is broken in *some other way* in 6.6.1 then we need a
>>>>> proper report or a bisect. Your logs don't show any issues other than
>>>>> the ubsan noise, which is not a regression.
>>>>>
>>>>> - Hector
>>>>>
>>>>
>>>> UBSAN noise seems to be fixed, Bluetooth not working though
>>>>
>>>> https://pastebin.com/HeVvMVk4
>>>>
>>>> Ill try setting .broken_le_coded = true,
>>>
>>> Now you have a probe timeout, which you didn't have before. That's a
>>> different problem.
>>>
>>> Please try this commit and see if it helps:
>>>
>>> https://github.com/AsahiLinux/linux/commit/8ec770b4f78fc14629705206e2db54d9d6439686
>>>
>>> If it's this then it's still not a regression, it's probably just random
>>> chance since I think the old timeout value was borderline for the older
>>> chips.
>>>
>>> - Hector
>>>
>>
>>
>> Hi
>>
>> I recently got a kernel tested with this patch as well as with .broken_le_coded = true,
>> Here are the logs: https://pastebin.com/BpfJuJKY
>>
>> Also, without .broken_le_coded = true, the bluetooth doesn't work, as specified in my previous email.
>
> So are you saying everything works now? If not, what doesn't work?
> "Bluetooth doesn't work" isn't useful information, especially in the
> absence of any useful error messages. You can't just dump dmesg logs at
> us, you have to *describe* what the problem is.
>
My bad for not specifying that. The user reports that the Bluetooth device is not recognised at all.
Also, broken_le_coded = true did not "fix" it.
Talking about dmesg, well not getting any logs regarding this message indeed is a frustrating thing for me, and bisecting seems to be the only option in my mind rn.
> If broken_le_coded = true "fixed" it then "bluetooth doesn't work" was a
> terrible bug report. What that quirk does is make *connecting/pairing to
> Bluetooth LE devices* work. Non-BLE devices already worked, the
> controller worked, scanning worked, etc. All that is useful information
> if you want to get support for issues. We can't magically divine what's
> wrong if you just send us a dmesg and say "it's broken". We need
> detailed information about exactly what works and what doesn't (e.g. the
> controller not showing up at all is VERY different from it showing up
> but not finding your device). The only reason we guessed this here is
> that this was a known issue that affected other chips. If we ever run
> into a 4377-specific issue that only you can reproduce, "bluetooth
> doesn't work" and no error logs really isn't going to get it fixed.
>
> - Hector