PCI: workaround hard-wired bus number V2

commit 71f6bd4 upstream. Fixes PCI device detection on IBM xSeries IBM 3850 M2 / x3950 M2 when using ACPI resources (_CRS). This is default, a manual workaround (without this patch) would be pci=nocrs boot param. V2: Add dev_warn if the workaround is hit. This should reveal how common such setups are (via google) and point to possible problems if things are still not working as expected. -> Suggested by Jan Beulich. Tested-by: [email protected] Signed-off-by: Yinghai Lu <[email protected]> Signed-off-by: Jesse Barnes <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
ar0n · Mar 1, 2012 · 608951f · 608951f
1 parent 74d54f5
commit 608951f
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
@@ -651,6 +651,11 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 	dev_dbg(&dev->dev, "scanning [bus %02x-%02x] behind bridge, pass %d\n",
 		secondary, subordinate, pass);
 
+	if (!primary && (primary != bus->number) && secondary && subordinate) {
+		dev_warn(&dev->dev, "Primary bus is hard wired to 0\n");
+		primary = bus->number;
+	}
+
 	/* Check if setup is sensible at all */
 	if (!pass &&
 	    (primary != bus->number || secondary <= bus->number)) {