Re: bug kernel 5.17, qualcom and intel adapters, unable to reliably connect to bluetooth devices

From: Chris Clayton <chris2553@googlemail.com>
To: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Chris Murphy <lists@colorremedies.com>,
	Bluetooth <linux-bluetooth@vger.kernel.org>
Subject: Re: bug kernel 5.17, qualcom and intel adapters, unable to reliably connect to bluetooth devices
Date: Thu, 24 Feb 2022 05:59:50 +0000	[thread overview]
Message-ID: <2ce6175c-74ec-8469-80a5-374bd1429542@googlemail.com> (raw)
In-Reply-To: <a35b4b75-bb64-89c8-bacd-d58ed8576272@googlemail.com>


On 23/02/2022 22:42, Chris Clayton wrote:
> Hi.
> 
> <snip>
> 
>>
>> We are starting to suspect this is not a new issue, it just become
>> easier to reproduce with newer kernels since the mgmt commands are now
>> handled by a different work/thread which probably takes longer to
>> respond hitting problems such as:
>>
>> https://github.com/bluez/bluez/issues/275#issuecomment-1020608282
>>
>> This has been fixed by:
>>
>> https://github.com/bluez/bluez/commit/faad125c5505b941f06c54525616e192a6369208
>> https://github.com/bluez/bluez/commit/5f378404bff6bbfea3f20e36535c494efa5066a5
>>
> 
> I cloned bluez, but that FTBFS, so I applied the two patches by hand.
> 
> After the first boot, my bluetooth devices connected fine. But after a poweroff and boot, they didn't. Nor did they on
> the third and fourth boots, so the patches don't seem to be the answer. (They couldn't really be anyway because changes
> to the kernel have broken user-space which I understand is a big no no unless there is a really compelling reason.)
> 
> I've gathered some diagnostics today and they are attached. They consist of 6 files containing the output from btmon and
> dmesg and the log file for the system daemons, which, of course, includes bluetoothd. There are 2 sets of these files -
> one from a boot that resulted in a system where my devices would not connect and another from a boot where they could

s/would not connect and another/would connect and another/

> not connect. You'll note that the btmon log is empty for a failed connection.
> 
> I also tried a bisection with v5.16 as good and v5.17-rc1 as bad. Unfortunately, I found several steps resulted in a
> kernel where bluetooth seemed to be substantially borked - to the extent that blueman was non-functional and clicking on
> the tray icon did not start up the blueman-manager application.
> 
> I also booted into a 5.16.10 kernel and connecting bluetooth devices worked flawlessly. (This was with the unpatched
> bluez daemon)
> 
> Chris
>> So the timer doesn't start until the request is sent. but obvoiusly
>> older versions of userspace don't have that fix so they end up
>> cancelling the loading of LTKs, this would explain why reloading the
>> daemon would make it work again.