diff --git a/sys/arm/nvidia/tegra_uart.c b/sys/arm/nvidia/tegra_uart.c
index e18b77ecc32..9c518997e85 100644
--- a/sys/arm/nvidia/tegra_uart.c
+++ b/sys/arm/nvidia/tegra_uart.c
@@ -136,6 +136,7 @@ static kobj_method_t tegra_methods[] = {
 	KOBJMETHOD(uart_receive,	ns8250_bus_receive),
 	KOBJMETHOD(uart_setsig,		ns8250_bus_setsig),
 	KOBJMETHOD(uart_transmit,	ns8250_bus_transmit),
+	KOBJMETHOD(uart_txbusy,		ns8250_bus_txbusy),
 	KOBJMETHOD(uart_grab,		tegra_uart_grab),
 	KOBJMETHOD(uart_ungrab,		tegra_uart_ungrab),
 	KOBJMETHOD_END
@@ -237,7 +238,7 @@ static device_method_t tegra_uart_bus_methods[] = {
 	DEVMETHOD(device_probe,		tegra_uart_probe),
 	DEVMETHOD(device_attach,	uart_bus_attach),
 	DEVMETHOD(device_detach,	tegra_uart_detach),
-	{ 0, 0 }
+	DEVMETHOD_END
 };
 
 static driver_t tegra_uart_driver = {
diff --git a/sys/dev/uart/uart_dev_ns8250.c b/sys/dev/uart/uart_dev_ns8250.c
index 4f2f8f7753b..f211084cb01 100644
--- a/sys/dev/uart/uart_dev_ns8250.c
+++ b/sys/dev/uart/uart_dev_ns8250.c
@@ -433,9 +433,10 @@ static kobj_method_t ns8250_methods[] = {
 	KOBJMETHOD(uart_receive,	ns8250_bus_receive),
 	KOBJMETHOD(uart_setsig,		ns8250_bus_setsig),
 	KOBJMETHOD(uart_transmit,	ns8250_bus_transmit),
+	KOBJMETHOD(uart_txbusy,		ns8250_bus_txbusy),
 	KOBJMETHOD(uart_grab,		ns8250_bus_grab),
 	KOBJMETHOD(uart_ungrab,		ns8250_bus_ungrab),
-	{ 0, 0 }
+	KOBJMETHOD_END
 };
 
 struct uart_class uart_ns8250_class = {
@@ -1070,6 +1071,17 @@ ns8250_bus_transmit(struct uart_softc *sc)
 	return (0);
 }
 
+bool
+ns8250_bus_txbusy(struct uart_softc *sc)
+{
+	struct uart_bas *bas = &sc->sc_bas;
+
+	if ((uart_getreg(bas, REG_LSR) & (LSR_TEMT | LSR_THRE)) !=
+	    (LSR_TEMT | LSR_THRE))
+		return (true);
+	return (false);
+}
+
 void
 ns8250_bus_grab(struct uart_softc *sc)
 {
diff --git a/sys/dev/uart/uart_dev_ns8250.h b/sys/dev/uart/uart_dev_ns8250.h
index 357f4e7f80d..324ff72f6e5 100644
--- a/sys/dev/uart/uart_dev_ns8250.h
+++ b/sys/dev/uart/uart_dev_ns8250.h
@@ -57,6 +57,7 @@ int ns8250_bus_receive(struct uart_softc *);
 int ns8250_bus_setsig(struct uart_softc *, int);
 int ns8250_bus_transmit(struct uart_softc *);
 void ns8250_bus_grab(struct uart_softc *);
+bool ns8250_bus_txbusy(struct uart_softc *);
 void ns8250_bus_ungrab(struct uart_softc *);
 
 #endif /* _DEV_UART_DEV_NS8250_H_ */
diff --git a/sys/dev/uart/uart_dev_snps.c b/sys/dev/uart/uart_dev_snps.c
index c3ada581c7c..b8b1f1f7814 100644
--- a/sys/dev/uart/uart_dev_snps.c
+++ b/sys/dev/uart/uart_dev_snps.c
@@ -101,6 +101,7 @@ static kobj_method_t snps_methods[] = {
 	KOBJMETHOD(uart_receive,	ns8250_bus_receive),
 	KOBJMETHOD(uart_setsig,		ns8250_bus_setsig),
 	KOBJMETHOD(uart_transmit,	ns8250_bus_transmit),
+	KOBJMETHOD(uart_txbusy,		ns8250_bus_txbusy),
 	KOBJMETHOD(uart_grab,		ns8250_bus_grab),
 	KOBJMETHOD(uart_ungrab,		ns8250_bus_ungrab),
 	KOBJMETHOD_END
diff --git a/sys/dev/uart/uart_dev_ti8250.c b/sys/dev/uart/uart_dev_ti8250.c
index 636f94872ce..1c575defa5f 100644
--- a/sys/dev/uart/uart_dev_ti8250.c
+++ b/sys/dev/uart/uart_dev_ti8250.c
@@ -105,6 +105,7 @@ static kobj_method_t ti8250_methods[] = {
 	KOBJMETHOD(uart_receive,	ns8250_bus_receive),
 	KOBJMETHOD(uart_setsig,		ns8250_bus_setsig),
 	KOBJMETHOD(uart_transmit,	ns8250_bus_transmit),
+	KOBJMETHOD(uart_txbusy,		ns8250_bus_txbusy),
 	KOBJMETHOD_END
 };
 
diff --git a/sys/dev/uart/uart_if.m b/sys/dev/uart/uart_if.m
index 516e8b0811d..7efe63a1024 100644
--- a/sys/dev/uart/uart_if.m
+++ b/sys/dev/uart/uart_if.m
@@ -38,6 +38,17 @@
 
 INTERFACE uart;
 
+CODE {
+	static uart_txbusy_t uart_default_txbusy;
+
+	static bool
+	uart_default_txbusy(struct uart_softc *this __unused)
+	{
+
+		return (false);
+	}
+};
+
 # attach() - attach hardware.
 # This method is called when the device is being attached. All resources
 # have been allocated. The transmit and receive buffers exist, but no
@@ -141,6 +152,16 @@ METHOD int transmit {
 	struct uart_softc *this;
 };
 
+# txbusy() - report if Tx is still busy.
+# This method is called by the tty glue for reporting upward that output is
+# still being drained despite sc_txbusy unset. Non-DEFAULT implementations
+# allow for extra checks, i. e. beyond what can be determined in ipend(),
+# that the Tx path actually is idle. For example, whether the last character
+# has left the transmit shift register in addition to the FIFO being empty.
+METHOD bool txbusy {
+	struct uart_softc *this;
+} DEFAULT uart_default_txbusy;
+
 # grab() - Up call from the console to the upper layers of the driver when
 # the kernel asks to grab the console. This is valid only for console
 # drivers. This method is responsible for transitioning the hardware
diff --git a/sys/dev/uart/uart_tty.c b/sys/dev/uart/uart_tty.c
index 672203cc593..faae077916f 100644
--- a/sys/dev/uart/uart_tty.c
+++ b/sys/dev/uart/uart_tty.c
@@ -388,9 +388,19 @@ uart_tty_busy(struct tty *tp)
 
 	sc = tty_softc(tp);
 	if (sc == NULL || sc->sc_leaving)
-                return (FALSE);
+                return (false);
 
-	return (sc->sc_txbusy);
+	/*
+	 * The tty locking is sufficient here; we may lose the race against
+	 * uart_bus_ihand()/uart_intr() clearing sc_txbusy underneath us, in
+	 * which case we will incorrectly but non-fatally report a busy Tx
+	 * path upward. However, tty locking ensures that no additional output
+	 * is enqueued before UART_TXBUSY() returns, which means that there
+	 * are no Tx interrupts to be lost.
+	 */
+	if (sc->sc_txbusy)
+		return (true);
+	return (UART_TXBUSY(sc));
 }
 
 static struct ttydevsw uart_tty_class = {