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Message-ID: <d9232cf5-b0ca-47f2-841d-45f5880368c8@penguintechs.org>
Date: Fri, 10 May 2024 12:49:34 -0700
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Subject: Re: [PATCH v1] Bluetooth: qca: Fix BT enable failure again for
 QCA6390 after warm reboot
Content-Language: en-US
To: Krzysztof Kozlowski <krzk@kernel.org>, Zijun Hu
 <quic_zijuhu@quicinc.com>, luiz.dentz@gmail.com, luiz.von.dentz@intel.com,
 marcel@holtmann.org
Cc: linux-bluetooth@vger.kernel.org, regressions@lists.linux.dev,
 stable@vger.kernel.org
References: <1714658761-15326-1-git-send-email-quic_zijuhu@quicinc.com>
 <5e5e869c-da12-4818-837e-55709f0c4db9@kernel.org>
From: Wren Turkal <wt@penguintechs.org>
In-Reply-To: <5e5e869c-da12-4818-837e-55709f0c4db9@kernel.org>
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On 5/3/24 3:16 AM, Krzysztof Kozlowski wrote:
> On 02/05/2024 16:06, Zijun Hu wrote:
>> Commit 272970be3dab ("Bluetooth: hci_qca: Fix driver shutdown on closed
>> serdev") will cause below regression issue:
>>
>> BT can't be enabled after below steps:
>> cold boot -> enable BT -> disable BT -> warm reboot -> BT enable failure
>> if property enable-gpios is not configured within DT|ACPI for QCA6390.
>>
>> The commit is to fix a use-after-free issue within qca_serdev_shutdown()
>> during reboot, but also introduces this regression issue regarding above
>> steps since the VSC is not sent to reset controller during warm reboot.
>>
>> Fixed by sending the VSC to reset controller within qca_serdev_shutdown()
>> once BT was ever enabled, and the use-after-free issue is also be fixed
>> by this change since serdev is still opened when send to serdev.
>>
>> Fixes: 272970be3dab ("Bluetooth: hci_qca: Fix driver shutdown on closed serdev")
>> Cc: stable@vger.kernel.org
>> Reported-by: Wren Turkal <wt@penguintechs.org>
>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218726
>> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
>> Tested-by: Wren Turkal <wt@penguintechs.org>
>> ---
>>   drivers/bluetooth/hci_qca.c | 5 ++---
> 
> I don't think this is v1. Version your patches properly and provide
> changelog.
> 
> I asked already *two times*:
> 1. On which kernel did you test it?
> 2. On which hardware did you test it?

I thought I had already chimed in with this information. I am using a 
Dell XPS 13 9310. It's the only hardware I have access to. I can say 
that the fix seems to work as advertised in that it fixes the warm boot 
issue I have been experiencing.

As a user, I vastly prefer a one time cold boot rather than having to do 
it every time. As such, I can do the test. However, I do not think that 
the patch not working in that case should block landing logic that 
empirically improved my experience with the hardware and minimizes the 
corner case to a much smaller corner (that of warm booting from an OS 
that improperly puts the device in a bad state to a Linux kernel with 
this UX improvement).

wt
-- 
You're more amazing than you think!