diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index cb1a027..0959430 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -299,8 +299,17 @@
 		r = bus->resource[i];
 		if (r == &ioport_resource || r == &iomem_resource)
 			continue;
-		if (r && (r->flags & type_mask) == type && !r->parent)
-			return r;
+		if (r && (r->flags & type_mask) == type) {
+			if (!r->parent)
+				return r;
+			/*
+			 * if there is no child under that, we should release
+			 * and use it. don't need to reset it, pbus_size_* will
+			 * set it again
+			 */
+			if (!r->child && !release_resource(r))
+				return r;
+		}
 	}
 	return NULL;
 }