x86/PCI: don't fall back to defaults if _CRS has no apertures
Host bridges that lead to things like the Uncore need not have any
I/O port or MMIO apertures. For example, in this case:
ACPI: PCI Root Bridge [UNC1] (domain 0000 [bus ff])
PCI: root bus ff: using default resources
PCI host bridge to bus 0000:ff
pci_bus 0000:ff: root bus resource [io 0x0000-0xffff]
pci_bus 0000:ff: root bus resource [mem 0x00000000-0x3fffffffffff]
we should not pretend those default resources are available on bus ff.
CC: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index a312e76..daa4249 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -404,7 +404,12 @@
kfree(sd);
} else {
get_current_resources(device, busnum, domain, &resources);
- if (list_empty(&resources))
+
+ /*
+ * _CRS with no apertures is normal, so only fall back to
+ * defaults or native bridge info if we're ignoring _CRS.
+ */
+ if (!pci_use_crs)
x86_pci_root_bus_resources(busnum, &resources);
bus = pci_create_root_bus(NULL, busnum, &pci_root_ops, sd,
&resources);