diff --git a/drivers/isdn/hisax/sedlbauer.c b/drivers/isdn/hisax/sedlbauer.c
index f16a47bcef485cc41dcf688e2d87a48ef1b7aa87..c0b97b893495a77332d7a8fc13d7fc41803b5c4d 100644
--- a/drivers/isdn/hisax/sedlbauer.c
+++ b/drivers/isdn/hisax/sedlbauer.c
@@ -558,7 +558,7 @@ static int setup_sedlbauer_isapnp(struct IsdnCard *card, int *bytecnt)
 				card->para[1] = pnp_port_start(pnp_d, 0);
 				card->para[0] = pnp_irq(pnp_d, 0);
 
-				if (!card->para[0] || !card->para[1]) {
+				if (card->para[0] == -1 || !card->para[1]) {
 					printk(KERN_ERR "Sedlbauer PnP:some resources are missing %ld/%lx\n",
 					       card->para[0], card->para[1]);
 					pnp_disable_dev(pnp_d);