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From:   Saravana Kannan <saravanak@google.com>
Date:   Wed, 3 Mar 2021 01:28:48 -0800
Message-ID: <CAGETcx8hAX2iv3KakM+pXeBPu_RFsUFLBBZvwDVxG95mAY=woA@mail.gmail.com>
Subject: Re: [PATCH v1 0/3] driver core: Set fw_devlink=on take II
To:     Michael Walle <michael@walle.cc>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Jon Hunter <jonathanh@nvidia.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Android Kernel Team <kernel-team@android.com>,
        LKML <linux-kernel@vger.kernel.org>
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On Wed, Mar 3, 2021 at 12:59 AM Michael Walle <michael@walle.cc> wrote:
>
> Am 2021-03-02 23:47, schrieb Saravana Kannan:
> > On Tue, Mar 2, 2021 at 2:42 PM Saravana Kannan <saravanak@google.com>
> > wrote:
> >>
> >> On Tue, Mar 2, 2021 at 2:24 PM Michael Walle <michael@walle.cc> wrote:
> >> >
> >> > Am 2021-03-02 22:11, schrieb Saravana Kannan:
> >> > > I think Patch 1 should fix [4] without [5]. Can you test the series
> >> > > please?
> >> >
> >> > Mh, I'm on latest linux-next (next-20210302) and I've applied patch 3/3
> >> > and
> >> > reverted commit 7007b745a508 ("PCI: layerscape: Convert to
> >> > builtin_platform_driver()"). I'd assumed that PCIe shouldn't be working,
> >> > right? But it is. Did I miss something?
> >>
> >> You need to revert [5].
> >
> > My bad. You did revert it. Ah... I wonder if it was due to
> > fw_devlink.strict that I added. To break PCI again, also set
> > fw_devlink.strict=1 in the kernel command line.
>
> Indeed, adding fw_devlink.strict=1 will break PCI again. But if
> I then apply 1/3 and 2/3 again, PCI is still broken. Just to be clear:
> I'm keeping the fw_devlink.strict=1 parameter.

Thanks for your testing! I assume you are also setting fw_devlink=on?

Hmmm... ok. In the working case, does your PCI probe before IOMMU? If
yes, then your results make sense.

If your PCI does probe after IOMMU and uses IOMMU, then I'm not sure
what else could be changing the order of the device probing. In any
case, glad that the default case works and we have a fix merged even
for .strict=1.

-Saravana