[PATCH] pci_dev to device_node fix

Jake Moilanen moilanen at austin.ibm.com
Tue Mar 16 09:00:27 EST 2004

> Anyway, I still don't see the problem. The PHB proper is not part of
> the PCI bus, or if it is, it will respond to a devfn normally.

Let me see if I can reiterate the problem a little clearer.  On a normal
pSeries box, they will have a "real" PHB.  When trying to read the PHB's
config space, the actual RTAS call would use devfn 0 for the PHB.  The
config cycles are done from the PHB.  So the assumption that the PHB
will have devfn 0 holds.

On a JS20, the PHB is a U3.  This is not a real PHB in terms of how we
think of it.  The config cycles are done directly from the bridges.  So
when we use devfn 0, we really want the first bridge.

So what I am trying to say, is that it is possible/legal for a device to
have a devfn of 0.  We can not make the assumption that the PHB will be
the one using devfn 0.  Since there is this overlap, we need a way need
another variable to tell us if the device is a PHB or not to


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