Index: linux-2.6.21.7/drivers/serial/pxa.c
===================================================================
--- linux-2.6.21.7.orig/drivers/serial/pxa.c
+++ linux-2.6.21.7/drivers/serial/pxa.c
@@ -235,15 +235,19 @@ static inline irqreturn_t serial_pxa_irq
 	struct uart_pxa_port *up = dev_id;
 	unsigned int iir, lsr;
 
+	serial_out(up, UART_MCR, serial_in(up, UART_MCR) & ~UART_MCR_RTS); // Clear RTS
 	iir = serial_in(up, UART_IIR);
 	if (iir & UART_IIR_NO_INT)
-		return IRQ_NONE;
+	{
+		//printk(KERN_WARNING "serial_pxa_irq: odd -- interrupt triggered, but no interrupt in IIR: %08x\n",iir);
+	}
 	lsr = serial_in(up, UART_LSR);
 	if (lsr & UART_LSR_DR)
 		receive_chars(up, &lsr);
 	check_modem_status(up);
 	if (lsr & UART_LSR_THRE)
 		transmit_chars(up);
+	serial_out(up, UART_MCR, serial_in(up, UART_MCR) | UART_MCR_RTS); // Assert RTS
 	return IRQ_HANDLED;
 }