On Thu, 2022-09-01 at 13:53 +1000, Michael Ellerman wrote: > > > > I sent two patches which do another steps to achieve it: > > https://lore.kernel.org/linuxppc-dev/20220817163927.24453-1-pali@xxxxxxxxxx/t/#u > > > > Main blocker is pci-OF-bus-map which is in direct conflict with > > CONFIG_PPC_PCI_BUS_NUM_DOMAIN_DEPENDENT and which used on chrp and pmac. > > And I have no idea if pci-OF-bus-map is still needed or not. > > Yeah thanks, I saw those patches. > > I can't find any code that refers to pci-OF-bus-map, so I'm inclined to > remove it entirely. > > But I'll do some more searching to see if I can find any references to > it in old code. Trying to remember ... :-) So this is what I recall at this point: - Ancient X11 didn't understand domains in /proc and thus would barf, which was the primary reason for not enabling them always iirc... - There might be something else with early PowerMacs (Grand Central chipset) where we have effectively two domains (gc and chaos) but overlapping bus numbers. There might still be pre-historical code in there that assumes it's that way though I can't see anything obvious. Paul might still have one of these :-) (PowerMac 7200/7500/8500/9500 afaik). - pci-OF-bus-map predates the PCI layer keeping track of the PCI/OF relationship. I don't believe it's still used anywhere in the kernel, though it's possible (unlikely ?) that some garbage remains in userspace that does. At this point, I wouldn't object to tearing this all out and just having domains always (and see what the fallout is). Cheers, Ben.
