diff options
| author | David Woodhouse <dwmw2@infradead.org> | 2007-08-22 21:01:11 (GMT) |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-08-23 02:52:44 (GMT) |
| commit | 20620d688ac6ff8ea01a873e46febf5a6a7909f1 (patch) | |
| tree | d96669333a906efd030016267aae93986434487a /drivers/serial | |
| parent | 187226f57f1381cfc63216979b4375f30e593795 (diff) | |
| download | linux-20620d688ac6ff8ea01a873e46febf5a6a7909f1.tar.xz | |
serial: don't optimise away baud rate changes when BOTHER is used
The uart_set_termios() function will bail out early without bothering to
touch the hardware, if it decides that nothing "relevant" has changed.
Unfortunately, its idea of "relevant" doesn't include c_[io]speed. So if
the baud rate bits are BOTHER and you just change the speed, the change
gets optimised away.
This patch makes it ignore the old Bfoo bits in c_cflag and just check
whether c_ispeed and c_ospeed have changed. Those integers are always set
appropriately for us by set_termios().
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/serial')
| -rw-r--r-- | drivers/serial/serial_core.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 030a606..a055f58 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -1146,11 +1146,14 @@ static void uart_set_termios(struct tty_struct *tty, struct ktermios *old_termio /* * These are the bits that are used to setup various - * flags in the low level driver. + * flags in the low level driver. We can ignore the Bfoo + * bits in c_cflag; c_[io]speed will always be set + * appropriately by set_termios() in tty_ioctl.c */ #define RELEVANT_IFLAG(iflag) ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK)) - if ((cflag ^ old_termios->c_cflag) == 0 && + tty->termios->c_ospeed == old_termios->c_ospeed && + tty->termios->c_ispeed == old_termios->c_ispeed && RELEVANT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0) return; |