On Mon, 2012-02-27 at 22:36 -0700, Bjorn Helgaas wrote: > > There's a lot of powerpc code that does this: > > bus_range = of_get_property(pcictrl, "bus-range", &len); > hose->first_busno = bus_range[0]; > hose->last_busno = bus_range[1]; > > That *looks* like it is discovering the bus number aperture. Is it? > If it is, why are we using the largest bus number found by > pci_scan_child_bus() rather than "last_busno"? We do that but we somewhat -also- rely on the core bumping it if it needs to make room :-) As I said, we are swimming in dirty waters between reverse engineered stuff we don't know 100% and "designed" stuff. I think we should have ways to more explicitely define what we want tho, ie whether hose->last_busno is just what happens to be the "current" bus number assigned by the firmware or the hard max. Maybe a pci flag ? On the other hand some platforms (all the ppc4xx ones for example) set the flag to reassign all busses ... but have limit on bus numbers simply because they have a memory mapped only config space and we don't have enough address space to ioremap it all on 32-bit. We need to fix them to use a fixmap entry to do atomic on-demand mapping of the config space and lift that restriction, but that isn't done yet. So I think those patches will need really careful handling on our side. Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
