On Fri, Oct 14, 2011 at 2:39 PM, Yinghai Lu [off-list ref] wrote:

On 10/14/2011 01:32 PM, Bjorn Helgaas wrote:

quoted

quoted

quoted

      int node;

@@ -353,11 +349,18 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)

              memcpy(bus->sysdata, sd, sizeof(*sd));
              kfree(sd);
      } else {
-             bus = pci_create_bus(NULL, busnum, &pci_root_ops, sd);
-             if (bus) {
-                     get_current_resources(device, busnum, domain, bus);
-                     bus->subordinate = pci_scan_child_bus(bus);
+             INIT_LIST_HEAD(&resources);
+             get_current_resources(device, busnum, domain, &resources);
+             if (!pci_use_crs) {
+                     pci_free_resource_list(&resources);
+                     x86_pci_root_bus_resources(busnum, &resources);
              }

You may need to update get_current_resources() to return status about handling _CRS...
and check that status insteaf of !pci_use_crs.

Is the current patch broken here?  I don't think it will be simpler to
have get_current_resources() return a status and check that.  But if
something's actually broken, I want to fix it, of course.

yes. if for some reason, _CRS is not handled right, that root bus resources will not get set to default res.

+             status = get_current_resources(device, busnum, domain, &resources);
+             if (status) {
+                     pci_free_resource_list(&resources);
+                     x86_pci_root_bus_resources(busnum, &resources);
             }

get_current_resources() will not return 0 if _CRS is not really used.

OK.  I think it was that way before, too.  We created the bus with
default resources, but the first thing get_current_resources() did was
clear them all out.  If there was a problem parsing _CRS, we never
went back and put the defaults back in.

But I think this will do what you suggest and is nicer than what I had before:

                INIT_LIST_HEAD(&resources);
                get_current_resources(device, busnum, domain, &resources);
                if (list_empty(&resources))
                        x86_pci_root_bus_resources(busnum, &resources);