2 files changed, 14 insertions, 0 deletions

diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index 926d4a5593fa..4d08b6d27c28 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -308,6 +308,17 @@ int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct f
         if (port->flags & ASYNC_INITIALIZED &&
                         port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
                 tty_wait_until_sent(tty, port->closing_wait);
+        if (port->drain_delay) {
+                unsigned int bps = tty_get_baud_rate(tty);
+                long timeout;
+
+                if (bps > 1200)
+                        timeout = max_t(long, (HZ * 10 * port->drain_delay) / bps,
+                                                                HZ / 10);
+                else
+                        timeout = 2 * HZ;
+                schedule_timeout_interruptible(timeout);
+        }
         return 1;
 }
 EXPORT_SYMBOL(tty_port_close_start);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 98694364c96f..bed5a3d40307 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -201,6 +201,9 @@ struct tty_port {
         unsigned char           *xmit_buf;      /* Optional buffer */
         int                     close_delay;    /* Close port delay */
         int                     closing_wait;   /* Delay for output */
+        int                     drain_delay;    /* Set to zero if no pure time
+                                                   based drain is needed else
+                                                   set to size of fifo */
 };
 
 /*