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Date: Mon, 8 Apr 2024 17:53:01 +0200
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Subject: Re: [PATCH v2 3/3] arm64: dts: qcom: msm8998: set
 qcom,no-msa-ready-indicator for wifi
To: Kalle Valo <kvalo@kernel.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
 Konrad Dybcio <konrad.dybcio@linaro.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
 Jeff Johnson <quic_jjohnson@quicinc.com>, ath10k
 <ath10k@lists.infradead.org>, wireless <linux-wireless@vger.kernel.org>,
 DT <devicetree@vger.kernel.org>, MSM <linux-arm-msm@vger.kernel.org>,
 Rob Herring <robh+dt@kernel.org>, Conor Dooley <conor+dt@kernel.org>,
 Pierre-Hugues Husson <phhusson@freebox.fr>, Arnaud Vrac <avrac@freebox.fr>,
 Bjorn Andersson <andersson@kernel.org>,
 Jami Kettunen <jamipkettunen@gmail.com>,
 Marijn Suijten <marijn.suijten@somainline.org>,
 Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
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From: Marc Gonzalez <mgonzalez@freebox.fr>
In-Reply-To: <87h6gh406w.fsf@kernel.org>
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On 04/04/2024 17:28, Kalle Valo wrote:

> Marc Gonzalez wrote:
> 
>> On 04/04/2024 13:57, Kalle Valo wrote:
>>
>>> Dmitry Baryshkov wrote:
>>>
>>>> I'd say, we should take a step back and actually verify how this was
>>>> handled in the vendor kernel.
>>>
>>> One comment related to this: usually vendor driver and firmware branches
>>> go "hand in hand", meaning that a version of driver supports only one
>>> specific firmware branch. And there can be a lot of branches. So even if
>>> one branch might have a check for something specific, there are no
>>> guarantees what the other N+1 branches do :/
>>
>> The consequences and ramifications of the above comment are not clear to me.
>>
>> Does this mean:
>> "It is pointless to analyze a given version (or even several versions)
>> of the vendor driver downstream, because there are exist a large number
>> of variations of the code." ?
> 
> I was trying to say that because the design philosophy between vendor
> drivers and upstream drivers is very different, we can't 100% trust
> vendor drivers. It's a very good idea to check what vendor drivers do
> but we just need to be careful before making any conclusions. Testing
> real hardware (and corresponding firmware) is the most reliable way to
> know how different products/firmware work, unfortunately.
> 
>> And thus, "it is nonsensical to try to "align" the mainline driver to
>> "the" vendor driver, as there is no single "vendor driver"" ?
> 
> No no, I'm not saying that. I have suffered this "N+1 different firmware
> branches behaving slighly differently" problem since ath6kl days so for
> me this is business as usual, sadly. I'm sure we can find a solution for
> ath10k.

Hello Kalle,

I can spin a v3, no problem.

Do you prefer:

Option A = never waiting for the MSA_READY indicator for ANYONE
Option B = not waiting for the MSA_READY indicator when qcom,no-msa-ready-indicator is defined
Option C = not waiting for the MSA_READY indicator for certain platforms (based on root compatible)
Option D = some other solution not yet discussed

Dmitry has tested Option A on 5 platforms, where it does not induce regressions.
I worked on msm8998, where Option A (or any equivalent) unbreaks WiFi.

Please provide guidance :)

Regards