diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index 24145c30c9b069104564df2f9e14b19f8728740b..6cc4358f68c12ad2c779c7837207ce875968cf40 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -1073,8 +1073,10 @@ static int set_serial_info(struct tty_struct *tty, struct serial_state *state,
 		    (new_serial.close_delay != port->close_delay) ||
 		    (new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
 		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
-		     (port->flags & ~ASYNC_USR_MASK)))
+		     (port->flags & ~ASYNC_USR_MASK))) {
+			tty_unlock();
 			return -EPERM;
+		}
 		port->flags = ((port->flags & ~ASYNC_USR_MASK) |
 			       (new_serial.flags & ASYNC_USR_MASK));
 		state->custom_divisor = new_serial.custom_divisor;
diff --git a/drivers/tty/serial/clps711x.c b/drivers/tty/serial/clps711x.c
index e6c3dbd781d61fd21e9dcafd3d85c1a0799f1f66..836fe2731234bbeabe690ef41ee230588cedea1b 100644
--- a/drivers/tty/serial/clps711x.c
+++ b/drivers/tty/serial/clps711x.c
@@ -154,10 +154,9 @@ static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id)
 		port->x_char = 0;
 		return IRQ_HANDLED;
 	}
-	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
-		clps711xuart_stop_tx(port);
-		return IRQ_HANDLED;
-	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+		goto disable_tx_irq;
 
 	count = port->fifosize >> 1;
 	do {
@@ -171,8 +170,11 @@ static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id)
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(port);
 
-	if (uart_circ_empty(xmit))
-		clps711xuart_stop_tx(port);
+	if (uart_circ_empty(xmit)) {
+	disable_tx_irq:
+		disable_irq_nosync(TX_IRQ(port));
+		tx_enabled(port) = 0;
+	}
 
 	return IRQ_HANDLED;
 }
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index bbbec4a74cfb5c30b3f9ba6c5f5fdfbed122d1ed..c2816f4948070157f1c969898bfde97b58bd6841 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1447,9 +1447,11 @@ static int pch_uart_verify_port(struct uart_port *port,
 			__func__);
 		return -EOPNOTSUPP;
 #endif
-		priv->use_dma = 1;
 		priv->use_dma_flag = 1;
 		dev_info(priv->port.dev, "PCH UART : Use DMA Mode\n");
+		if (!priv->use_dma)
+			pch_request_dma(port);
+		priv->use_dma = 1;
 	}
 
 	return 0;