From db106df32d679db151b48a09543b03ee41cb2580 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Tue, 2 Sep 2014 17:39:15 -0400 Subject: [PATCH] serial: Fix send_xchar() handlers START_CHAR() & STOP_CHAR() can be disabled if set to '\0' (__DISABLED_CHAR). UART drivers which define a send_xchar() handler must not transmit __DISABLED_CHAR. Document requirement. Affected drivers: sunsab sunhv cc: David S. Miller cc: Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- Documentation/serial/driver | 2 ++ drivers/tty/serial/sunhv.c | 3 +++ drivers/tty/serial/sunsab.c | 3 +++ 3 files changed, 8 insertions(+) diff --git a/Documentation/serial/driver b/Documentation/serial/driver index 3bba1aeb799c..ba64e4b892e9 100644 --- a/Documentation/serial/driver +++ b/Documentation/serial/driver @@ -140,6 +140,8 @@ hardware. will append the character to the circular buffer and then call start_tx() / stop_tx() to flush the data out. + Do not transmit if ch == '\0' (__DISABLED_CHAR). + Locking: none. Interrupts: caller dependent. diff --git a/drivers/tty/serial/sunhv.c b/drivers/tty/serial/sunhv.c index 20521db2189f..25d43ce8b318 100644 --- a/drivers/tty/serial/sunhv.c +++ b/drivers/tty/serial/sunhv.c @@ -268,6 +268,9 @@ static void sunhv_send_xchar(struct uart_port *port, char ch) unsigned long flags; int limit = 10000; + if (ch == __DISABLED_CHAR) + return; + spin_lock_irqsave(&port->lock, flags); while (limit-- > 0) { diff --git a/drivers/tty/serial/sunsab.c b/drivers/tty/serial/sunsab.c index b9598b227a45..0af75f8b98a4 100644 --- a/drivers/tty/serial/sunsab.c +++ b/drivers/tty/serial/sunsab.c @@ -468,6 +468,9 @@ static void sunsab_send_xchar(struct uart_port *port, char ch) struct uart_sunsab_port *up = (struct uart_sunsab_port *) port; unsigned long flags; + if (ch == __DISABLED_CHAR) + return; + spin_lock_irqsave(&up->port.lock, flags); sunsab_tec_wait(up); -- 2.20.1