linux-kernel - Re: [PATCH] regulator: qcom-rpmh: Use PROBE_FORCE

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Date:   Fri, 24 Mar 2023 09:12:00 -0500
From:   Andrew Halaney <ahalaney@...hat.com>
To:     Marek Szyprowski <m.szyprowski@...sung.com>
Cc:     Doug Anderson <dianders@...omium.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] regulator: qcom-rpmh: Use PROBE_FORCE_SYNCHRONOUS

On Fri, Mar 24, 2023 at 12:18:53PM +0100, Marek Szyprowski wrote:
> Hi,
> 
> On 23.03.2023 23:08, Doug Anderson wrote:
> > On Thu, Mar 23, 2023 at 3:05 PM Marek Szyprowski
> > <m.szyprowski@...sung.com> wrote:
> >> Restore synchronous probing for 'qcom,pm8150-rpmh-regulators' because
> >> otherwise the UFSHC device is not properly initialized on QRB5165-RB5
> >> board.
> >>
> >> Fixes: ed6962cc3e05 ("regulator: Set PROBE_PREFER_ASYNCHRONOUS for drivers between 4.14 and 4.19")
> >> Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
> >> ---
> >>   drivers/regulator/qcom-rpmh-regulator.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> > I don't object to this patch landing temporarily, but can you provide
> > any more details, please? On Qualcomm Chromebooks I'm not seeing any
> > issues with RPMH regulators probing asynchronously, so I can only
> > assume that there's a bug in the UFSHC driver that's being tickled.
> 
> You are right. I've analyzed this case further and it turned out that it 
> was my fault. In short - 'rootwait' kernel cmdline parameter was missing 
> and root was specified as '/dev/sda7'.
> 
> UFSHC driver properly retried probing after it cannot get its 
> regulators, but it happened at the same time when kernel tried to mount 
> rootfs. I was confused that this is really a regulator issue, because 
> the mentioned /dev/sda* devices were properly reported as available in 
> the system in the root mounting failure message, but adding the 
> 'rootwait' cmdline parameter fixed this problem. It would be safe to 
> revert this change. I'm really sorry for the false report and the noise.
> 

It looks like this got applied, but reading your above message makes it
seem like this patch is not necessary. Did I understand that correctly?

If so we should see if Mark can drop / revert it?

Thanks,
Andrew