The patch titled
serial: don't optimise away baud rate changes when BOTHER is used
has been added to the -mm tree. Its filename is
dont-optimise-away-baud-rate-changes-when-bother-is-used.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: serial: don't optimise away baud rate changes when BOTHER is used
From: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Acked-by: Alan Cox <alan@xxxxxxxxxx>
Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/serial/serial_core.c | 18 ++++++++++++++----
1 files changed, 14 insertions(+), 4 deletions(-)
diff -puN drivers/serial/serial_core.c~dont-optimise-away-baud-rate-changes-when-bother-is-used drivers/serial/serial_core.c
--- a/drivers/serial/serial_core.c~dont-optimise-away-baud-rate-changes-when-bother-is-used
+++ a/drivers/serial/serial_core.c
@@ -1146,13 +1146,23 @@ static void uart_set_termios(struct tty_
/*
* 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
+ */
+#ifdef CIBAUD
+#define RELEVANT_CFLAG(cflag) ((cflag) & ~(CIBAUD|CBAUD)
+#else
+#define RELEVANT_CFLAG(cflag) ((cflag) & ~(CBAUD)
+#endif
#define RELEVANT_IFLAG(iflag) ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
-
if ((cflag ^ old_termios->c_cflag) == 0 &&
- RELEVANT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 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) {
+ printk("No relevant change\n");
return;
+ }
uart_change_speed(state, old_termios);
_
Patches currently in -mm which might be from dwmw2@xxxxxxxxxxxxx are
use-mutex-instead-of-semaphore-in-the-mtd-st-m25pxx-driver.patch
use-mutex-instead-of-semaphore-in-the-mtd-dataflash-driver.patch
git-ubi.patch
git-battery.patch
dont-optimise-away-baud-rate-changes-when-bother-is-used.patch
jffs2-convert-to-new-aops.patch
char-n_r3964-use-wait_event_interruptible.patch
mismatching-declarations-of-revision-strings-in-hisax.patch
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