On Friday 16 January 2015 15:16:28 Yinghai Lu wrote: > On Fri, Jan 16, 2015 at 3:15 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: > > On Thu, Jan 15, 2015 at 5:43 PM, Yijing Wang <wangyijing@xxxxxxxxxx> wrote: > >> Pci_bus_add_devices() should not be placed in pci_scan_bus(). > >> Now pci device will be added to driver core once its > >> creation. All things left in pci_bus_add_devices() are > >> driver attachment and other trivial sysfs things. > >> Pci_scan_bus() should be the function responsible for > >> scanning PCI devices, not including driver attachment. > >> Other, some callers(m68k,unicore32,alpha) of pci_scan_bus() > >> will call pci_bus_size_bridges() and pci_bus_assign_resources() > >> after pci_scan_bus(). > >> > >> E.g. > >> In m68k > >> mcf_pci_init() > >> pci_scan_bus() > >> ... > >> pci_bus_add_devices() --- try to attach driver > >> pci_fixup_irqs() > >> pci_bus_size_bridges() > >> pci_bus_assign_resources() > >> > >> It is not correct, resources should be assigned correctly > >> before attaching driver. > > > No, for booting path, at that time pci drivers are *NOT* loaded yet. This may be true for the m68k example, and traditionally for all PCI hosts, but as we move to a more modular architecture with drivers/pci/hosts, you can have PCI host drivers that are loadable modules and get loaded after the built-in drivers are initialized, or you can have host drivers that depend on a resource (clock, regulator, reset, gpio, ...) that in turn comes from a driver that gets initialized later. Arnd -- 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
