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Date:   Tue, 14 Jun 2022 10:02:21 +0200
From:   Stephan Gerhold <stephan.gerhold@kernkonzept.com>
To:     Paul Menzel <pmenzel@molgen.mpg.de>
Cc:     Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        linux-arm-msm@vger.kernel.org, linux-bluetooth@vger.kernel.org,
        Stephan Gerhold <stephan@gerhold.net>
Subject: Re: [PATCH] Bluetooth: btqcomsmd: Fix command timeout after setting
 BD address
Message-ID: <YqhAjSDEC72c0e5d@kernkonzept.com>
References: <20220613110745.3778356-1-stephan.gerhold@kernkonzept.com>
 <9d8238ba-500e-3490-8a25-e7b72bab175f@molgen.mpg.de>
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Hi Paul,

On Mon, Jun 13, 2022 at 06:09:33PM +0200, Paul Menzel wrote:
> Am 13.06.22 um 13:07 schrieb Stephan Gerhold:
> > The Bluetooth firmware seems to become unresponsive for a while after
> 
> Please mention the device with the problematic firmware.
> 

Will add a comment in v2. It seems to affect pretty much all devices
that make use of the "btqcomsmd" driver.

> > setting the BD address. At least on recent kernel versions this often
> 
> The commit referenced in the Fixes tag is in Linux 4.9. Can you please name
> the oldest Linux kernel version you experienced the problem with.
> 

This is quite hard to say. It definitely became more apparent in the
last few months (so at least 5.17+). But since it's a timing problem
it's influenced by various side effects. For example, it is less likely
to happen the more hardware functionality you enable on a board (because
other interrupts come in and might cause the necessary delay).

I believe that the problem also exists in some form on Linux 4.9,
even though it might be harder to trigger it there.

Thanks,
Stephan