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>
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@ -1146,11 +1146,14 @@ static void uart_set_termios(struct tty_struct *tty, struct ktermios *old_termio
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/*
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* These are the bits that are used to setup various
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* flags in the low level driver.
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* flags in the low level driver. We can ignore the Bfoo
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* bits in c_cflag; c_[io]speed will always be set
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* appropriately by set_termios() in tty_ioctl.c
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*/
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#define RELEVANT_IFLAG(iflag) ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
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if ((cflag ^ old_termios->c_cflag) == 0 &&
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tty->termios->c_ospeed == old_termios->c_ospeed &&
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tty->termios->c_ispeed == old_termios->c_ispeed &&
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RELEVANT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0)
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return;
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