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Commit db106df3 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
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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 <davem@davemloft.net>
cc: <sparclinux@vger.kernel.org>
Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fba594a8

Documentation/serial/driver

+2 −0
Original line number Diff line number Diff line
@@ -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.

drivers/tty/serial/sunhv.c

+3 −0
Original line number Diff line number Diff line
@@ -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) {

drivers/tty/serial/sunsab.c

+3 −0
Original line number Diff line number Diff line
@@ -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);