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Message-ID: <930736f3-696c-4076-93fb-d879691bac66@quicinc.com>
Date: Mon, 22 Apr 2024 19:25:22 +0800
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Subject: Re: [PATCH v5 2/2] Bluetooth: qca: Fix BT enable failure for
 QCA_QCA6390 after disable then warm reboot
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        <luiz.dentz@gmail.com>, <luiz.von.dentz@intel.com>,
        <marcel@holtmann.org>
CC: <linux-bluetooth@vger.kernel.org>, <bartosz.golaszewski@linaro.org>,
        <wt@penguintechs.org>, <regressions@lists.linux.dev>
References: <1713650800-29741-1-git-send-email-quic_zijuhu@quicinc.com>
 <1713771497-5733-1-git-send-email-quic_zijuhu@quicinc.com>
 <1713771497-5733-3-git-send-email-quic_zijuhu@quicinc.com>
 <f744a2ba-f842-454a-a04f-76207f0db9bf@linaro.org>
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From: quic_zijuhu <quic_zijuhu@quicinc.com>
In-Reply-To: <f744a2ba-f842-454a-a04f-76207f0db9bf@linaro.org>
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On 4/22/2024 3:42 PM, Krzysztof Kozlowski wrote:
> On 22/04/2024 09:38, Zijun Hu wrote:
>> From: Zijun Hu <zijuhu@qti.qualcomm.com>
>>
>> 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 QCA_QCA6390.
>>
>> The commit is to fix a use-after-free issue within qca_serdev_shutdown()
>> during reboot, but also introduces this new 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")
>> Reported-by: Wren Turkal <wt@penguintechs.org>
> 
> NAK. This is way too much. Previous discussion is going, I asked there
> questions and before any answers happen, you keep sending new version.
> This leads to previous discussion gone/missed.
> 
> You ignored several questions and feedbacks.
> 
> Best regards,
> Krzysztof
> 
i believe my commit message explains WHAT/WHY/HOW about this issue.

1) the qca_serdev_shutdown() was introduced by my below commit
Commit 7e7bbddd029b ("Bluetooth: hci_qca: Fix qca6390 enable failure
after warm reboot")

2) then Krzysztof's below commit was made to fix use-after-free issue
but also causes discussed regression issue.
Commit 0b7015132878 ("Bluetooth: btusb: mediatek: add MediaTek
devcoredump support")

3) my fix will solve both this issue and the use-after-free issue.