On Wed, Jun 26, 2013 at 3:55 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > On Wed, Jun 26, 2013 at 4:31 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: >> On Wed, Jun 26, 2013 at 3:26 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: >>> On Wed, Jun 26, 2013 at 3:18 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: >>>> On Tue, Jun 25, 2013 at 10:22 AM, Mika Westerberg >>>> <mika.westerberg@xxxxxxxxxxxxxxx> wrote: >>>>> Thunderbolt PCI-to-PCI bridges typically use BIOS "assisted" enumeration. >>>>> This means that the BIOS will allocate bridge resources based on some >>>>> assumptions of a maximum Thunderbolt chain. It also disables native PCIe >>>>> hotplug of the root port where the Thunderbolt host router is connected. >> ... >> During acpi hotplug, firmare could do extra help for us like assign >> some resources to pci device bars, so it is NOT "boot-time". > > Really? How can firmware assign BARs at hotplug-time? I mean, > obviously firmware *can* write things to the BARs before giving the > device to the OS, but how would it know what to write? should be acpi code, or SMI code or even BMC firmware via sideband. > I assume the > OS owns the address space, and it can change the upstream bridge > windows or the BARs of another device on the bus at any time, subject > to the OS's own issues as far as quiescing or unbinding drivers, etc., > but without coordinating with the BIOS. for thunderbolt or dock with acpiphp, then all children devices/bridges should not have drivers loaded yet. Yinghai -- 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
