ARM: 5688/1: ks8695_serial: disable_irq() lockup

disable_irq() cannot be called from interrupt context without self imposed deadlock. This was happening in ks8695uart_stop_tx().
Signed-off-by: Dick Hollenbeck <dick@softplc.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/serial/serial_ks8695.c

@@ -110,7 +110,11 @@ static struct console ks8695_console;
 static void ks8695uart_stop_tx(struct uart_port *port)
 {
 	if (tx_enabled(port)) {
-		disable_irq(KS8695_IRQ_UART_TX);
+		/* use disable_irq_nosync() and not disable_irq() to avoid self
+		 * imposed deadlock by not waiting for irq handler to end,
+		 * since this ks8695uart_stop_tx() is called from interrupt context.
+		 */
+		disable_irq_nosync(KS8695_IRQ_UART_TX);
 		tx_enable(port, 0);
 	}
 }