Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210130040344.2807439-1-saravanak@google.com>
 <CAGETcx941J7Zhrf=ZjO6PW0fiax5VXcV3gbsLQfM_wU_U0EnYw@mail.gmail.com> <CAMuHMdUGkRmjnkSXQ4VNz5crMJ0S4xUvrV=BenOf96Y_bepPSw@mail.gmail.com>
In-Reply-To: <CAMuHMdUGkRmjnkSXQ4VNz5crMJ0S4xUvrV=BenOf96Y_bepPSw@mail.gmail.com>
From:   Saravana Kannan <saravanak@google.com>
Date:   Mon, 1 Feb 2021 19:00:21 -0800
Message-ID: <CAGETcx896XEv8OqOe4eGncjOYb=v6+g1RWkpo5g0hTbfp4Os+w@mail.gmail.com>
Subject: Re: [PATCH v1 0/2] Make fw_devlink=on more forgiving
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Marc Zyngier <maz@kernel.org>,
        Tudor Ambarus <Tudor.Ambarus@microchip.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Android Kernel Team <kernel-team@android.com>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Mon, Feb 1, 2021 at 2:40 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Saravana,
>
> On Sat, Jan 30, 2021 at 5:09 AM Saravana Kannan <saravanak@google.com> wrote:
> > On Fri, Jan 29, 2021 at 8:03 PM Saravana Kannan <saravanak@google.com> wrote:
> > > This patch series solves two general issues with fw_devlink=on
> > >
> > > Patch 1/2 addresses the issue of firmware nodes that look like they'll
> > > have struct devices created for them, but will never actually have
> > > struct devices added for them. For example, DT nodes with a compatible
> > > property that don't have devices added for them.
> > >
> > > Patch 2/2 address (for static kernels) the issue of optional suppliers
> > > that'll never have a driver registered for them. So, if the device could
> > > have probed with fw_devlink=permissive with a static kernel, this patch
> > > should allow those devices to probe with a fw_devlink=on. This doesn't
> > > solve it for the case where modules are enabled because there's no way
> > > to tell if a driver will never be registered or it's just about to be
> > > registered. I have some other ideas for that, but it'll have to come
> > > later thinking about it a bit.
> > >
> > > These two patches might remove the need for several other patches that
> > > went in as fixes for commit e590474768f1 ("driver core: Set
> > > fw_devlink=on by default"), but I think all those fixes are good
> > > changes. So I think we should leave those in.
> > >
> > > Marek, Geert,
> > >
> > > Can you try this series on a static kernel with your OF_POPULATED
> > > changes reverted? I just want to make sure these patches can identify
> > > and fix those cases.
> > >
> > > Tudor,
> > >
> > > You should still make the clock driver fix (because it's a bug), but I
> > > think this series will fix your issue too (even without the clock driver
> > > fix). Can you please give this a shot?
> >
> > Marek, Geert, Tudor,
> >
> > Forgot to say that this will probably fix your issues only in a static
> > kernel. So please try this with a static kernel. If you can also try
> > and confirm that this does not fix the issue for a modular kernel,
> > that'd be good too.
>
> Thanks for your series!
>
> For the modular case, this series has no impact, as expected (i.e. fails
> to boot, no I/O devices probed).
> With modules disabled, both r8a7791/koelsch and r8a77951/salvator-xs
> seem to boot fine, except for one issue on koelsch:

Thanks a lot for testing the series!

Regarding the koelsch issue, do you not see it with your OF_POPULATED
fix for rcar-sysc driver? But only see if you revert it and use this
series?

>
> dmesg:
>
>     +i2c-demux-pinctrl i2c-12: failed to setup demux-adapter 0 (-19)
>     +i2c-demux-pinctrl i2c-13: failed to setup demux-adapter 0 (-19)
>     +i2c-demux-pinctrl i2c-14: failed to setup demux-adapter 0 (-19)
>
>     -  #0: rsnd-dai.0-ak4642-hifi
>     +  No soundcards found.
>
> regulator_summary:
>
>     -13-0050-vcc                   0    0mA     0mV     0mV
>     -13-0039-dvdd-3v               1    0mA     0mV     0mV
>     -13-0039-bgvdd                 1    0mA     0mV     0mV
>     -13-0039-pvdd                  1    0mA     0mV     0mV
>     -13-0039-dvdd                  1    0mA     0mV     0mV
>     -13-0039-avdd                  1    0mA     0mV     0mV
>
> pm_genpd_summary:
>
>     -/devices/platform/soc/e6518000.i2c  suspended                  0
>     -/devices/platform/soc/e6530000.i2c  suspended                  0
>     -/devices/platform/soc/e6520000.i2c  suspended                  0
>
> These are all symptoms of the same issue: i2c buses and devices are not
> probed, due to the use of the i2c demuxer.
> I guess the fw_devlink tracker doesn't consider "i2c-parent" links?

No, it doesn't parse "i2c-parent". Ugh... looked at it. It's going to
be a problem to parse because it requires the parents to be disbled in
DT and then fixes them up during run time. fw_devlink can handle DT
overlay changing a specific node, but the problem is that the consumer
DT node doesn't get changed. So the i2c-parent will first be parsed,
fw_devlink will notice they are disabled, so it'll ignore them. Then
those nodes are enabled, but the i2c-parent isn't reparsed because the
consumer isn't updated.

> Note that I only tested this on R-Car Gen2 and Gen3.
> I did not test this on Renesas SH/R-Mobile or RZ/A SoCs.

Thanks for any testing you can do :)

So overall, this series seems to be helping, but doesn't cover 100% of
the cases. So I suppose this is still a useful series. I'll be happy
to take any Tested-by or Reviewed-by.

-Saravana