On Mon, Feb 27, 2012 at 1:49 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: > On Mon, Feb 27, 2012 at 11:17 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: >> On Mon, Feb 27, 2012 at 12:08 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: > >>>> This doesn't feel right to me. You're allocating a new struct device >>>> here, but the arch likely already has one. In fact, I think we even >>>> passed it in to pci_create_root_bus(). >>> >>> no. >>> >>> original pci_create_root_bus() will create one dummy struct device and >>> use it as parent for bus->dev. >>> >>>> >>>> On x86, we already have an ACPI device for the host bridge, and now >>>> we'll have a second one. (Actually a *third* one, because PNPACPI >>>> also has one, but that's a long-standing problem.) >>> >>> not related. >> >> OK. Can you educate me? What is the device we pass in, what does the >> dummy one correspond to, why do we have two, what's the difference, >> etc., etc.? > > for every bus will have ->bridge, and that is device pointer. to pci > bridge dev. > > for root bus, there is not pci bridge for that. So create_root_bus > allocate local dummy one. > > that dummy device will be bus->dev's parent. > > Now pci_host_bridge is added, and it is allocated, so just put the > struct device into that pci_host_bridge. > > and use pci_host_bridge->dev as parent of root bus->dev's parent. What's the device passed in to pci_create_root_bus()? Why is that different than the root bus dev's parent? -- 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
