--- 2.6/drivers/serial/8250_pnp.c.orig	2007-10-16 14:18:19.000000000 +0800
+++ 2.6/drivers/serial/8250_pnp.c	2007-10-16 14:18:30.000000000 +0800
@@ -431,6 +431,9 @@
 
 	memset(&port, 0, sizeof(struct uart_port));
 	port.irq = pnp_irq(dev, 0);
+	/* No irq is assigned for the port, fallback to "no irq" hack */
+	if (port.irq == -1)
+		port.irq = 0; 
 	if (pnp_port_valid(dev, 0)) {
 		port.iobase = pnp_port_start(dev, 0);
 		port.iotype = UPIO_PORT;