pci_dlpar.c & probe mode

Benjamin Herrenschmidt benh at kernel.crashing.org
Sat Mar 25 08:48:52 EST 2006


On Fri, 2006-03-24 at 10:16 -0600, John Rose wrote:
> > I noticed that pcibios_add_pci_devices() test the platform type to
> > decide wether to do a device-tree based probe or a direct PCI probe. Why
> > can't it use ppc_md.probe_mode() like the rest of the PCI code does ?
> 
> I can't see a good reason either! :)  I'll have a patch in two shakes of
> a lamb's tail.  
> 
> On a related note, I don't understand why devtree-based probe is only
> desirable for the LPAR case (on pSeries).  

I think it was dictated by a conservative approach .. it's necessary for
LPAR and we didn't want to change the behaviour on older machines...
besides, things like bare metal may not provide the PCI nodes in OF and
use the same code base.

> Also, do we anticipate future probe modes for new platforms or
> something?  Adding such logic to ppc_md seems like mucho infrastructure
> to answer a simple question (lpar or not).  For exmaple, _machine gets
> used all over the pmac code.

_machine is gone, see my last patch ... It's not only about lpar or
not .. on powermac, it's really a per-bus & per machine generation
decision wether to trust OF or not..

Ben.





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