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Date:   Wed, 03 Mar 2021 11:21:05 +0100
From:   Michael Walle <michael@walle.cc>
To:     Saravana Kannan <saravanak@google.com>
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>
Subject: Re: [PATCH v1 0/3] driver core: Set fw_devlink=on take II
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Am 2021-03-03 10:28, schrieb Saravana Kannan:
> 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?

I've applied patch 3/3 and added nothing to the commandline, so yes.

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

Yes that was the conclusion last time. That the probe is deferred and
the __init section is already discarded when there might a second
try of the probe.

So I guess, Patch 1/3 and Patch 2/3 doesn't fix that and the drivers
still need to be converted to builtin_platform_driver(), right?

> 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

-michael