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Commit eb424fd2 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
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uart_get_baud_rate: stop mangling termios 



Russell King noticed this one: We have to avoid replacing B0 when we pick a
baud rate for a "hung up" port.  Ugly but the proper fix is in the tty layer
and means changing the tty<->serial interfaces so we will defer that for now.

[akpm@linux-foundation.org: fix uninitialised var]
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e991a2bd

drivers/serial/serial_core.c

+11 −4
Original line number Original line Diff line number Diff line
@@ -329,13 +329,15 @@ EXPORT_SYMBOL(uart_update_timeout); 
 *	If it's still invalid, we try 9600 baud.

 *	If it's still invalid, we try 9600 baud.

 *

 *

 *	Update the @termios structure to reflect the baud rate

 *	Update the @termios structure to reflect the baud rate

 *	we're actually going to be using.

 *	we're actually going to be using. Don't do this for the case

 *	where B0 is requested ("hang up").

 */

 */

unsigned int

unsigned int

uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,

uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,

		   struct ktermios *old, unsigned int min, unsigned int max)

		   struct ktermios *old, unsigned int min, unsigned int max)

{

{

	unsigned int try, baud, altbaud = 38400;

	unsigned int try, baud, altbaud = 38400;

	int hung_up = 0;

	upf_t flags = port->flags & UPF_SPD_MASK;

	upf_t flags = port->flags & UPF_SPD_MASK;





	if (flags == UPF_SPD_HI)

	if (flags == UPF_SPD_HI)
@@ -360,8 +362,10 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, 
		/*

		/*

		 * Special case: B0 rate.

		 * Special case: B0 rate.

		 */

		 */

		if (baud == 0)

		if (baud == 0) {

			hung_up = 1;

			baud = 9600;

			baud = 9600;

		}





		if (baud >= min && baud <= max)

		if (baud >= min && baud <= max)

			return baud;

			return baud;
@@ -373,7 +377,9 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, 
		termios->c_cflag &= ~CBAUD;

		termios->c_cflag &= ~CBAUD;

		if (old) {

		if (old) {

			baud = tty_termios_baud_rate(old);

			baud = tty_termios_baud_rate(old);

			tty_termios_encode_baud_rate(termios, baud, baud);

			if (!hung_up)

				tty_termios_encode_baud_rate(termios,

								baud, baud);

			old = NULL;

			old = NULL;

			continue;

			continue;

		}

		}
@@ -382,6 +388,7 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, 
		 * As a last resort, if the quotient is zero,

		 * As a last resort, if the quotient is zero,

		 * default to 9600 bps

		 * default to 9600 bps

		 */

		 */

		if (!hung_up)

			tty_termios_encode_baud_rate(termios, 9600, 9600);

			tty_termios_encode_baud_rate(termios, 9600, 9600);

	}

	}