From: Amit Pundir <amit.pundir@linaro.org>
To: krzysztof.kozlowski@linaro.org,
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: agross@kernel.org, arnd@arndb.de, bjorn.andersson@linaro.org,
devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, olof@lixom.net, robh@kernel.org,
sboyd@kernel.org, Konrad Dybcio <konrad.dybcio@somainline.org>
Subject: Re: Removal of qcom,board-id and qcom,msm-id
Date: Mon, 23 May 2022 11:11:29 +0530 [thread overview]
Message-ID: <CAMi1Hd161=vc2eLVsnYVeeU6mNH8Fx8XfiQMUe_K=LbjyetSZw@mail.gmail.com> (raw)
In-Reply-To: <20220522195138.35943-1-konrad.dybcio@somainline.org>
On Mon, 23 May 2022 at 01:22, Konrad Dybcio
<konrad.dybcio@somainline.org> wrote:
>
> Hi,
>
> removing these properties will not bring almost any benefit (other than making
> some checks happy any saving some <200 LoC) and will make the lives of almost
> all people doing independent development for linux-on-msm harder. There are
> almost unironically like 3 people outside Linaro and QUIC who have
> non-vendor-fused development boards AND the sources to rebuild the
> bootloader on their own. Making it harder to boot is only going to
> discourage people from developing on these devices, which is already not
> that pleasant, especially with newer platforms where you have to fight with
> the oh-so-bright ideas of Android boot chain..
>
> This only concerns devices released before sm8350, as the new ones will not
> even boot with these properties present (or at least SONY Sagami, but I
> doubt it's an isolated case), so other than completing support for older
> devices, it won't be an issue going forward, anyway. But there are give
> or take 50 locked down devices in mainline right now, and many more waiting
> to be upstreamed in various downstream close-to-mainline trees that should
> not be disregarded just because Qualcomm is far from the best at making
> their BSP software stack clean.
>
> One solution is to chainload another, (n+1)-stage bootloader, but this is
> not ideal, as:
>
> 1) the stock bootloader can boot Linux just fine on most devices (except
> for single exceptions, where beloved OEMs didn't implement arm64 booting or
> something)
>
> 2) the boot chain on MSM is already 3- or 4- stage and adding to that will
> only create an unnecessary mess
>
> 3) the job of kernel people is not to break userspace. If the
> device can not even exit bootloader after a kernel upgrade, it's a big
> failure.
>
> If you *really really really* want these either gone or documented, we can
> for example use them in the SOCID driver, read the values from DTB and
> compare against what SMEM has to say and for example print a warning when
> there are inconsistencies or use it as a fallback when it fails for any
> reason, such as using a newer SoC on an older kernel, without updates
> for SOCID read (which are sometimes necessary, which was the case for 8450
> recently, iirc).
>
> My stance is to just leave them as is, as moving them anywhere, or removing
> them at all will cause unnecessary mess and waste time that could have been
> spent on more glaring issues..
I couldn't have put it better myself. I suggest we document these
properties, if that is the blocker, and keep them. A lot has changed
in the last 7 years, we now have dozens of devices booting upstream
kernel using these properties.
And fwiw, I have not used dtbTool before, if anything I'd rather
explore dtb overlays.
Regards,
Amit Pundir
>
> Konrad
next prev parent reply other threads:[~2022-05-23 5:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-19 10:44 Removal of qcom,board-id and qcom,msm-id Krzysztof Kozlowski
2022-05-19 11:39 ` Dmitry Baryshkov
2022-05-19 11:53 ` Krzysztof Kozlowski
2022-05-19 12:46 ` Dmitry Baryshkov
[not found] ` <20220519221227.B66D3C385AA@smtp.kernel.org>
2022-05-20 1:39 ` Dmitry Baryshkov
2022-05-20 7:00 ` Krzysztof Kozlowski
2022-05-22 10:26 ` Krzysztof Kozlowski
2022-05-22 10:50 ` Dmitry Baryshkov
2022-05-22 19:51 ` Konrad Dybcio
2022-05-23 5:41 ` Amit Pundir [this message]
2022-05-23 7:21 ` Krzysztof Kozlowski
2022-05-23 12:02 ` Konrad Dybcio
2022-05-23 12:14 ` Krzysztof Kozlowski
2022-05-23 15:29 ` Konrad Dybcio
2022-05-23 16:41 ` Trilok Soni
2022-05-23 21:34 ` Bjorn Andersson
2022-05-23 22:13 ` Trilok Soni
2022-05-23 21:29 ` Rob Clark
2022-05-23 21:50 ` Bjorn Andersson
2022-05-23 22:18 ` Dmitry Baryshkov
2022-05-25 17:36 ` Stephan Gerhold
2022-05-26 7:16 ` Krzysztof Kozlowski
2022-06-22 8:21 ` Dmitry Baryshkov
2022-06-22 11:53 ` Konrad Dybcio
2022-06-23 9:55 ` Dmitry Baryshkov
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