On Thu, Jan 19, 2012 at 3:23 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: > On Thu, Jan 19, 2012 at 2:13 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: >> On Thu, Jan 19, 2012 at 1:42 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: >>> please check attached patch. >> >> You added bus_max to pci_scan_root_bus(). I'd prefer to pass a >> pointer to a struct resource, as we do for io & mem resources. > > Well that depends. Well, I suppose it does. On what? >> I'd >> like to move away from pci_scan_root_bus() and toward a >> pci_scan_host_bridge() (as in the patches I posted) that takes all the >> host bridge-related info: parent, domain, resources (including bus >> number range), ops, sysdata. I don't like the current scheme of >> "create it with defaults and fix them later." > > No, struct host bridge is bad idea. you are tracking host bridge and > peer root bus the same time. Obviously host bridges and root buses are related, but it'd be useful if you could give some clue about *why* you think this is a bad idea. Redundancy, complication, what? Root buses are special in important ways, and we currently don't have a way to deal with that. For example, everything below a host bridge has the same domain, and we don't have a good place to keep the domain. The busn_res you add to struct pci_bus is only useful for root buses, so I don't think pci_bus is quite the right place. >> struct pci_bus already has secondary & subordinate. I don't think >> adding a "struct resource busn_res" adds useful information except for >> the root bus, where the bus number range comes from something external >> like _CRS rather than from the upstream bridge config. > > no, we need that to tracking the busn usage. aka insert them into > iobusn_resource tree. If we want a tree, I think we should just convert pci_bus.secondary and subordinate to a struct resource and insert that. Otherwise we have redundant information. > late it should be convert to list head even. for handling transparent bridge. I think you're talking about a host bridge that passes multiple bus number ranges, e.g., a PNP0A08 device with "[bus 00-3f] [bus 80-ff]" in _CRS. That makes sense. I haven't seen anything like that, but it seems like it would be legal. But that wouldn't make sense for a P2P bridge, so it doesn't seem like pci_bus is the right place for it. Bjorn -- 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
