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From:   Rob Herring <robh+dt@kernel.org>
Date:   Wed, 29 Aug 2018 20:05:47 -0500
Message-ID: <CAL_JsqLJ9QMHCMqGKpCouP1rTEO+cMGA1es94qAH+ukLsR31jg@mail.gmail.com>
Subject: Re: v4.17 regression: PowerMac G3 won't boot, was Re: [PATCH v5 1/3]
 of: cache phandle nodes to reduce cost of of_find_node_by_phandle()
To:     fthain@telegraphics.com.au
Cc:     Frank Rowand <frank.rowand@sony.com>, userm57@yahoo.com,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Chintan Pandya <cpandya@codeaurora.org>,
        devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
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On Wed, Aug 29, 2018 at 7:44 PM Finn Thain <fthain@telegraphics.com.au> wrote:
>
> Hi Frank,
>
> Linux v4.17 and later will no longer boot on a G3 PowerMac. The boot hangs
> very early, before any video driver loads.
>
> Stan and I were able to bisect the regression between v4.16 and v4.17 and
> arrived at commit 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of
> of_find_node_by_phandle()").
>
> I don't see any obvious bug in 0b3ce78e90fc or b9952b5218ad. But if you
> revert these from v4.18 (which is also affected) that certainly resolves
> the issue.

Perhaps a bad assumption on phandle values causing a problem. Can you
provide a dump of all the phandle or linux,phandle values from
/proc/device-tree.

Rob