diff --git a/drivers/pnp/isapnp/core.c b/drivers/pnp/isapnp/core.c
index f2e0179962e2..3ac5b123215a 100644
--- a/drivers/pnp/isapnp/core.c
+++ b/drivers/pnp/isapnp/core.c
@@ -1049,6 +1049,10 @@ static int __init isapnp_init(void)
 		printk(KERN_INFO "isapnp: ISA Plug & Play support disabled\n");
 		return 0;
 	}
+#ifdef CONFIG_PPC_MERGE
+	if (check_legacy_ioport(_PIDXR) || check_legacy_ioport(_PNPWRP))
+		return -EINVAL;
+#endif
 #ifdef ISAPNP_REGION_OK
 	if (!request_region(_PIDXR, 1, "isapnp index")) {
 		printk(KERN_ERR "isapnp: Index Register 0x%x already used\n", _PIDXR);