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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: Alan Cox <alan@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox 2008-04-28 02:14:07 -07:00 committed by Linus Torvalds
parent e991a2bd4f
commit eb424fd21c
1 changed files with 11 additions and 4 deletions
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13
drivers/serial/serial_core.c
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@ -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);
} }