Hi Finn,
On 08/29/18 17:44, Finn Thain 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.
>
> I did see this in the kernel messages:
>
> Duplicate name in PowerPC,750, renamed to "l2-cache#1"
> Duplicate name in mac-io, renamed to "ide#1"
> Duplicate name in ide#1, renamed to "atapi-disk#1"
> Duplicate name in multifunc-device, renamed to "pci1799,1#1"
>
> No idea whether that's relevant; I haven't done any further investigation.
> Complete dmesg output is attached. Please let me know if there's any more
> information you need to help find the bug.
>
> Thanks.
I don't have any useful answers yet, but I am following the thread and have
also quickly scanned the two commits for any obvious cause. I will look
into this some more, but have a few other tasks that I need to complete
first.
A long shot, but something to consider, is that I failed to cover the
cases of dynamic devicetree updates (removing nodes that contain a
phandle) in ways other than overlays. Michael Ellerman has reported
such a problem for powerpc/mobility with of_detach_node(). A patch to
fix that is one of the tasks I need to complete.
-Frank
