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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()
From:   Benjamin Herrenschmidt <benh@kernel.crashing.org>
To:     Mac User <userm57@yahoo.com>, Rob Herring <robh+dt@kernel.org>
Cc:     fthain@telegraphics.com.au, Frank Rowand <frank.rowand@sony.com>,
        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>
Date:   Fri, 31 Aug 2018 14:35:39 +1000
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On Thu, 2018-08-30 at 20:39 -0600, Mac User wrote:
> On 8/29/18 7:05 PM, Rob Herring wrote:
> 
> > 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
> 
> Rob,
> 
> As suggested by Finn, I installed device-tree-compiler and
> powerpc-ibm-utils.
>  
> Running "dtc -I fs -H both /sys/firmware/devicetree/base"
> resulted in the following errors:
> 
> DTC: fs->dts on file "/sys/firmware/devicetree/base"
> ERROR (name_properties): "name" property in
> /pci/multifunc-device/pci1799,1#1 is incorrect ("pci1799,1" instead of
> base node name)
> ERROR (name_properties): "name" property in /pci/mac-io/ide#1 is
> incorrect ("ide" instead of base node name)
> ERROR (name_properties): "name" property in
> /pci/mac-io/ide#1/atapi-disk#1 is incorrect ("atapi-disk" instead of
> base node name)
> ERROR (name_properties): "name" property in /cpus/PowerPC,750/l2-cache#1
> is incorrect ("l2-cache" instead of base node name)
> ERROR: Input tree has errors, aborting (use -f to force output)
> 
> If I force output with "-f", the resulting file has no occurrences 
> of "phandle".

Are you booting with BootX or Open Firmware ?

> Running "lsprop /proc/device-tree | grep -i phandle" results in no 
> output.
> 
> Please let me know if there's some other way to get information that 
> would be helpful.
> 
> thanks
> 
> -Stan