--- //depot/yahoo/ybsd_9/src/sys/dev/uart/uart_dev_ns8250.c	2011-11-02 23:46:55.000000000 0000
+++ /home/peter/share/ybsd_9/sys/dev/uart/uart_dev_ns8250.c	2011-11-02 23:46:55.000000000 0000
@@ -601,6 +601,8 @@
 			ipend |= SER_INT_BREAK;
 		if (lsr & LSR_RXRDY)
 			ipend |= SER_INT_RXREADY;
+		if (sc->sc_txbusy && (lsr & LSR_TEMT))
+			ipend |= SER_INT_TXIDLE;
 	} else {
 		if (iir & IIR_TXRDY)
 			ipend |= SER_INT_TXIDLE;