On Thu, Jul 21, 2016 at 12:46:03AM +0200, Rafael J. Wysocki wrote: > On Wednesday, July 20, 2016 02:35:43 PM Bjorn Helgaas wrote: > > On Tue, Jun 28, 2016 at 09:41:19PM -0700, Aaron Durbin wrote: > > > On Fri, Jun 24, 2016 at 12:34 PM, Aaron Durbin <adurbin@xxxxxxxxxx> wrote: > > > > acpi_init() and pci_subsys_init() are both subsys_initcalls during > > > > boot up. I'm not sure if the ordering is dumb luck or not, but > > > > acpi_init() is called prior to pci_subsys_init(). The conflict error > > > > is spit out from pcibios_resource_survey() by way of pci_subsys_init() > > > > subsys_initcall. However, the PCI device scanning is kicked off prior > > > > to this through acpi_scan_init() by way of acpi_init() > > > > subsys_initcall. The conflict error occurs because there's already > > > > the child ACPI device in the resource tree. I'm not sure when/where > > > > those ACPI devices' resources are added, but clearly they are sitting > > > > in there since the conflict was found. > > > > I think the acpi_init()/pci_subsys_init() ordering is correct. The > > ACPI namespace is primary. A PCI hierarchy originates at a PCI host > > bridge in the ACPI namespace, so we should enumerate the ACPI > > namespace first, and when we find a PCI host bridge, we should > > enumerate the PCI devices below it. > > > > That said, I think it is correct mostly by accident and it would be > > nice if it were more explicit. > > No, it isn't by accident. > > The enumeration of PCI devices under a PCI host bridge discovered via ACPI > starts in acpi_pci_root_add() which quite explicitly is only called after > enumerating the ACPI namespace entirely. > > acpi_bus_scan() has two passes now, one is to call acpi_bus_check_add() for > all namespace objects and the other is the acpi_bus_attach() pass where > all things like acpi_pci_root_add() are called. I meant the ordering between acpi_init() and pci_subsys_init(). They're both subsys_initcalls, so their ordering is determined by link order, which is not at all obvious (at least to me), since acpi_init() is in drivers/acpi and pci_subsys_init() is in arch/x86. If they were both in drivers, the drivers/Makefile would make it pretty obvious. But finding the order of "arch" relative to "drivers" in Makefile is less obvious. acpi_init() has to be before pci_subsys_init(), and it is. I shouldn't have said it was by accident, just that it's non-obvious. 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
