16550A UART: RHR irq enable bit also masks the Rx timeout irq.

The "Rx timeout" (aka. Character Timeout Indication) has no separate mask
bit in the IER register and according to the specs reading RHR is the only
way to reset the irq.  However on the hardware (tested on OMAP2 UART which
is an extended 16550A) the RHR_IT bit in IER disables the irc, too.  Linux
bluetooth serial dongle driver for N800 depends on this behavior.


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5239 c046a42c-6fe2-441c-8c8c-71466251a162

hw/serial.c

@@ -191,7 +191,7 @@ static void serial_update_irq(SerialState *s)
 
     if ((s->ier & UART_IER_RLSI) && (s->lsr & UART_LSR_INT_ANY)) {
         tmp_iir = UART_IIR_RLSI;
-    } else if (s->timeout_ipending) {
+    } else if ((s->ier & UART_IER_RDI) && s->timeout_ipending) {
         tmp_iir = UART_IIR_CTI;
     } else if ((s->ier & UART_IER_RDI) && (s->lsr & UART_LSR_DR)) {
         if (!(s->fcr & UART_FCR_FE)) {