diff --git a/arch/loongarch/pci/acpi.c b/arch/loongarch/pci/acpi.c
index 5ba4d3a169b21b869bba40f08f15b686ea18bac1..38b2a45473e0aa40e5a77e2e853c1f9043a57350 100644
--- a/arch/loongarch/pci/acpi.c
+++ b/arch/loongarch/pci/acpi.c
@@ -346,6 +346,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 	struct acpi_pci_root_ops *root_ops;
 	int domain = root->segment;
 	int busnum = root->secondary.start;
+	struct pci_host_bridge *host;
 
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info) {
@@ -386,8 +387,17 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 			return NULL;
 		}
 
-		pci_bus_size_bridges(bus);
-		pci_bus_assign_resources(bus);
+		/* If we must preserve the resource configuration, claim now */
+		host = pci_find_host_bridge(bus);
+		if (host->preserve_config)
+			pci_bus_claim_resources(bus);
+
+		/*
+		 * Assign whatever was left unassigned. If we didn't claim above,
+		 * this will reassign everything.
+		 */
+		pci_assign_unassigned_root_bus_resources(bus);
+
 		list_for_each_entry(child, &bus->children, node)
 			pcie_bus_configure_settings(child);
 	}