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Message-ID: <CAFqH_52T7QATdhJktDQPx7CeBTKocZfZ8LPAZp4+RMqsOHu0gw@mail.gmail.com>
Date: Wed, 26 Feb 2020 18:15:38 +0100
From: Enric Balletbo Serra <eballetbo@...il.com>
To: Maxime Ripard <maxime@...no.tech>
Cc: Stephen Boyd <sboyd@...nel.org>,
Guillaume Tucker <guillaume.tucker@...labora.com>,
Jerome Brunet <jbrunet@...libre.com>,
Chen-Yu Tsai <wens@...e.org>, Mark Brown <broonie@...nel.org>,
Tomeu Vizoso <tomeu.vizoso@...labora.com>,
Michael Turquette <mturquette@...libre.com>,
Enric Balletbo i Serra <enric.balletbo@...labora.com>,
Kevin Hilman <khilman@...libre.com>, mgalka@...labora.com,
linux-clk@...r.kernel.org,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: next/master bisection: baseline.login on sun8i-h2-plus-orangepi-zero
Hi all,
Missatge de Maxime Ripard <maxime@...no.tech> del dia dt., 25 de febr.
2020 a les 15:34:
>
> On Wed, Feb 19, 2020 at 03:49:47PM -0800, Stephen Boyd wrote:
> > Adding some Allwinner folks. Presumably there is some sort of clk that
> > is failing to calculate a phase when it gets registered. Maybe that's
> > because the parent isn't registered yet?
>
> It's simpler than that :)
>
> > Quoting Guillaume Tucker (2020-02-17 23:45:41)
> > > Hi Stephen,
> > >
> > > Please see the bisection report below about a boot failure.
> > >
> > > Reports aren't automatically sent to the public while we're
> > > trialing new bisection features on kernelci.org but this one
> > > looks valid.
> > >
> > > There's nothing in the serial console log, probably because it's
> > > crashing too early during boot. I'm not sure if other platforms
> > > on kernelci.org were hit by this in the same way, it's tricky to
> > > tell partly because there is no output. It should possible to
> > > run it again with earlyprintk enabled in BayLibre's test lab
> > > though.
> > >
> > > Thanks,
> > > Guillaume
> > >
> > >
> > > On 18/02/2020 02:14, kernelci.org bot wrote:
> > > > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> > > > * This automated bisection report was sent to you on the basis *
> > > > * that you may be involved with the breaking commit it has *
> > > > * found. No manual investigation has been done to verify it, *
> > > > * and the root cause of the problem may be somewhere else. *
> > > > * *
> > > > * If you do send a fix, please include this trailer: *
> > > > * Reported-by: "kernelci.org bot" <bot@...nelci.org> *
> > > > * *
> > > > * Hope this helps! *
> > > > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> > > >
> > > > next/master bisection: baseline.login on sun8i-h2-plus-orangepi-zero
> > > >
> > > > Summary:
> > > > Start: c25a951c50dc Add linux-next specific files for 20200217
> > > > Plain log: https://storage.kernelci.org//next/master/next-20200217/arm/multi_v7_defconfig/gcc-8/lab-baylibre/baseline-sun8i-h2-plus-orangepi-zero.txt
> > > > HTML log: https://storage.kernelci.org//next/master/next-20200217/arm/multi_v7_defconfig/gcc-8/lab-baylibre/baseline-sun8i-h2-plus-orangepi-zero.html
> > > > Result: 2760878662a2 clk: Bail out when calculating phase fails during clk registration
> > > >
> > > > Checks:
> > > > revert: PASS
> > > > verify: PASS
> > > >
> > > > Parameters:
> > > > Tree: next
> > > > URL: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> > > > Branch: master
> > > > Target: sun8i-h2-plus-orangepi-zero
> > > > CPU arch: arm
> > > > Lab: lab-baylibre
> > > > Compiler: gcc-8
> > > > Config: multi_v7_defconfig
> > > > Test case: baseline.login
> > > >
> > > > Breaking commit found:
> > > >
> > > > -------------------------------------------------------------------------------
> > > > commit 2760878662a290ac57cff8a5a8d8bda8f4dddc37
> > > > Author: Stephen Boyd <sboyd@...nel.org>
> > > > Date: Wed Feb 5 15:28:02 2020 -0800
> > > >
> > > > clk: Bail out when calculating phase fails during clk registration
> > > >
> > > > Bail out of clk registration if we fail to get the phase for a clk that
> > > > has a clk_ops::get_phase() callback. Print a warning too so that driver
> > > > authors can easily figure out that some clk is unable to read back phase
> > > > information at boot.
> > > >
> > > > Cc: Douglas Anderson <dianders@...omium.org>
> > > > Cc: Heiko Stuebner <heiko@...ech.de>
> > > > Suggested-by: Jerome Brunet <jbrunet@...libre.com>
> > > > Signed-off-by: Stephen Boyd <sboyd@...nel.org>
> > > > Link: https://lkml.kernel.org/r/20200205232802.29184-5-sboyd@kernel.org
> > > > Acked-by: Jerome Brunet <jbrunet@...libre.com>
> > > >
> > > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > > > index dc8bdfbd6a0c..ed1797857bae 100644
> > > > --- a/drivers/clk/clk.c
> > > > +++ b/drivers/clk/clk.c
> > > > @@ -3457,7 +3457,12 @@ static int __clk_core_init(struct clk_core *core)
> > > > * Since a phase is by definition relative to its parent, just
> > > > * query the current clock phase, or just assume it's in phase.
> > > > */
> > > > - clk_core_get_phase(core);
> > > > + ret = clk_core_get_phase(core);
> > > > + if (ret < 0) {
> > > > + pr_warn("%s: Failed to get phase for clk '%s'\n", __func__,
> > > > + core->name);
> > > > + goto out;
> > > > + }
>
> The thing is, clk_core_get_phase actually returns the phase on success :)
>
> So, when you actually have a phase returned, and not an error, you end
> up with a positive, non-zero, value for ret.
>
> And since it's the latest assignment of that value, and that we return
> ret all the time, even on success, we end up returning that positive,
> non-zero value to __clk_register, which in turn tests whether it's
> non-zero for success (it's not), and then proceeds to garbage collect
> everything.
>
> I guess we're just the odd ones actually returning non-zero phases at
> init time and in kernelci.
>
Just to note that not only Allwiner is affected, Rockchip is also
affected by this issue. Reverting the patch fixes the issue for me,
but the patch proposed by Maxime [1] does _NOT_ fixes the issue for
Rockchip, there is something else, I'll take a look. I can't answer
that patch because didn't reach my inbox.
Regards,
Enric
[1] https://patchwork.kernel.org/patch/11403837/
> I'll send a patch
>
> Maxime
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