linux-kernel - Re: [PATCH V5 4/4] arm64: dts: qcom: sm8550: Add max-sd-hs-hz property

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <23c29fb7-c0a4-4519-9b8d-e68255b83a10@kernel.org>
Date: Thu, 4 Sep 2025 12:51:45 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
 Sarthak Garg <quic_sartgarg@...cinc.com>,
 Ulf Hansson <ulf.hansson@...aro.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Bjorn Andersson <andersson@...nel.org>,
 Konrad Dybcio <konradybcio@...nel.org>,
 Adrian Hunter <adrian.hunter@...el.com>
Cc: linux-mmc@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
 quic_nguyenb@...cinc.com, quic_rampraka@...cinc.com,
 quic_pragalla@...cinc.com, quic_sayalil@...cinc.com,
 quic_nitirawa@...cinc.com, quic_bhaskarv@...cinc.com, kernel@....qualcomm.com
Subject: Re: [PATCH V5 4/4] arm64: dts: qcom: sm8550: Add max-sd-hs-hz
 property

On 04/09/2025 10:36, Konrad Dybcio wrote:
> On 9/3/25 10:21 AM, 'Krzysztof Kozlowski' via kernel wrote:
>> On 03/09/2025 10:04, Sarthak Garg wrote:
>>> Due to board-specific hardware constraints particularly related
>>> to level shifter in this case the maximum frequency for SD High-Speed
>>> (HS) mode must be limited to 37.5 MHz to ensure reliable operation of SD
>>> card in HS mode.
>>>
>>> This is achieved by introducing the `max-sd-hs-hz` property in the
>>> device tree, allowing the controller to operate within safe frequency
>>> limits for HS mode.
>>>
>>
>> Probably we will now replicate the same discussion... And it will be
>> happening every time you send the same and not reflect it in commit msg.
>>
>> Bindings say board setup, this commit msg says board config, but the
>> patch says SoC. This is not correct.
> 
> Both are correct, looking at the problem from two perspectives.
> 
> The bindings description mentions board-specific limitations (e.g. because
> "the board's electrical design does not allow one to achieve the full rated
> frequency that the SoC can otherwise do, in a stable way")
> 
> Here the author tries to argue that almost all SM8550 boards are broken
> in this sense, because the reference design did not feature the required
> passive components, making most (derivative) designs sort of "broken by
> default" - and only some (if any?) vendors decided to go with the
> additional components required to lift this limitation.
> 
> This in turn makes it fair to assume the developer experience would benefit
> from having the SD card high speed modes always work (with the slight speed
> cap which may not be required for the 1 or 2 designs that took the extra
> step) without each board DT creator having to track down this property
> separately.

And then if you send same v3, I will ask the same. Can the author
finally write commit msgs reflecting discussions and previous disagreements?

Reviewers questions happen for a reason, so sending the same means
person ignored that reason.

Best regards,
Krzysztof