Index: sys/dev/uart/uart_dev_ns8250.c
===================================================================
--- sys/dev/uart/uart_dev_ns8250.c
+++ sys/dev/uart/uart_dev_ns8250.c
@@ -178,13 +178,21 @@
 		 * limit high enough to handle large FIFOs and integrated
 		 * UARTs. The HP rx2600 for example has 3 UARTs on the
 		 * management board that tend to get a lot of data send
-		 * to it when the UART is first activated.
+		 * to it when the UART is first activated.  Assume that we
+		 * have finished draining if LSR_RXRDY is not asserted both
+		 * prior to and after a DELAY; but as long as LSR_RXRDY is
+		 * asserted, read (and discard) characters as quickly as
+		 * possible.
 		 */
-		limit=10*4096;
-		while ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) && --limit) {
+		for (limit = 10 * 4096; limit > 0; limit--) {
+			if ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) == 0) {
+				DELAY(delay << 2);
+				uart_barrier(bas);
+				if ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) == 0)
+					break;
+			}
 			(void)uart_getreg(bas, REG_DATA);
 			uart_barrier(bas);
-			DELAY(delay << 2);
 		}
 		if (limit == 0) {
 			/* printf("ns8250: receiver appears broken... "); */