Machine check during PCI scan on PMac G5

Benjamin Herrenschmidt benh at
Sun Oct 3 10:51:46 EST 2004

On Sun, 2004-10-03 at 10:36, Segher Boessenkool wrote:
> >> Argh... again ! Looks like the box doesn't like us to probe the
> >> PCI device that is there. Can you print out the precise devfn
> >> bus number & offset where the machine check happens ?
> >
> > The first occurence is devfn 48, bus number 0, offset 14.
> That's the "header type" field on the GEM shim.
> I'd rather not have this fixed by the device-tree check, for
> various reasons; note that this issue probably is related to the
> "config space not readable while GEM is in sleep mode" problem
> on older Macs.  Is the GEM powered on during boot, on these boxes?

I'm suprised, I'm not sure it's actually GEM (Andreas, is the Sungem
properly functionning on this box after this fix ?). I think the
numbering of the Shims can change from firmware to firmware, it's
more probably one of the USBs. There is code in pmac_feature.c to
power up the GEM (but only if it has a device-node).

I think the proper solution is the filter from the device-tree on
Apple G5s, at least for now, though OF itself probably has a property
somewhere that tells it which slots to probe and not to probe, I need
to find it.


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