>>> On 23.02.11 at 22:00, Bjorn Helgaas <bjorn.helgaas@xxxxxx> wrote: > There are good reasons why a BIOS might hide a PCI device. For > example, if SMM code uses a PCI device, the BIOS must prevent the > OS from moving it. One way would be to hide the device from PCI > enumeration and then expose it via the ACPI namespace, where the > _CRS/_PRS/_SRS methods allow the BIOS to control the configuration. > > I know there's some tension here -- things like EDAC want to use > devices we "know" are there, while the BIOS might need to hide things > to keep our mitts off them. I'm not sure there's a reliable way to > tell when it's safe for us to go around the BIOS intent. I had tried for several months to get a statement from Intel on this behavior, without any success. > Nobody wants to give up EDAC functionality, but in the long term, it > might be better to say, "Well, your OEM doesn't want to support > functionality X even though the hardware is there, so consider that > when you're choosing your next system." Or maybe we taint the kernel > when we circumvent the BIOS like this. At a minimum, I think we should > log a note in dmesg. That's already the case: "PCI: Discovered peer bus ..." Jan -- 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
