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Date: Thu, 14 Dec 2023 15:01:50 +0100
From: Johan Hovold <johan@kernel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Rob Clark <robdclark@gmail.com>, linux-arm-msm@vger.kernel.org,
	Rob Clark <robdclark@chromium.org>, Andy Gross <agross@kernel.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] soc: qcom: pmic_glink: Fix boot when QRTR=m
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References: <20231213210644.8702-1-robdclark@gmail.com>
 <ZXqr0RFw9KsP876v@hovoldconsulting.com>
 <CAA8EJpoSvaq9imP-dT4p=4jveZyFmh=OoWOP7jWGo4OYkHQDTA@mail.gmail.com>
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On Thu, Dec 14, 2023 at 01:04:43PM +0200, Dmitry Baryshkov wrote:
> On Thu, 14 Dec 2023 at 09:16, Johan Hovold <johan@kernel.org> wrote:
> >
> > On Wed, Dec 13, 2023 at 01:06:43PM -0800, Rob Clark wrote:
> > > From: Rob Clark <robdclark@chromium.org>
> > >
> > > We need to bail out before adding/removing devices, if we are going
> > > to -EPROBE_DEFER.  Otherwise boot will get stuck forever at
> > > deferred_probe_initcall().
> >
> > Can please you expand on why this is a problem here in the commit
> > message?
> >
> > The aux devices appear to be tore down correctly in the probe error
> > paths so how exactly does that lead to deferred_probe_initcall() being
> > stuck? This sounds like we may have a problem elsewhere which this patch
> > is papering over.
> 
> This is a known problem. Successful probes during the probe deferral
> loop causes the whole loop to be reiterated. Creating child devices
> usually results in  a successful probe. Aso I thought that just
> creating new device also causes a reprobe, but I can not find any
> evidence now.

This still needs to be described in the commit message.

Only a successful probe should trigger a reprobe, and when the child
devices are registered the parent is not yet on the deferred probe list.
So something is not right or missing here.

Johan