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Subject[PATCH 3/3] tty: support CIBAUD without BOTHER
Since commit edc6afc54968 ("[PATCH] tty: switch to ktermios and new
framework") arbitrary baud rates can be requested using BOTHER and input
rates can be requested using the termios CIBAUD bits (CBAUD shifted
IBSHIFT bits).

This functionality has been conditionally compiled depending on whether
an architecture defines BOTHER and IBSHIFT respectively, but would in
fact fail to compile unless both symbols were defined due to cross

Relax the IBSHIFT => BOTHER dependency so that an architecture could
theoretically support CIBAUD without the Linux-specific BOTHER, while
hopefully making the current conditional-compilation directives a bit
less confusing.

Note that the long-term goal is still to have all architectures support
both features, so an alternative could just be to have the lot depend on

Signed-off-by: Johan Hovold <>
drivers/tty/tty_baudrate.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/tty_baudrate.c b/drivers/tty/tty_baudrate.c
index 3e827a3d48d5..7576ceace571 100644
--- a/drivers/tty/tty_baudrate.c
+++ b/drivers/tty/tty_baudrate.c
@@ -100,11 +100,11 @@ speed_t tty_termios_input_baud_rate(struct ktermios *termios)

if (cbaud == B0)
return tty_termios_baud_rate(termios);
+#ifdef BOTHER
/* Magic token for arbitrary speed via c_ispeed*/
if (cbaud == BOTHER)
return termios->c_ispeed;
if (cbaud & CBAUDEX) {
cbaud &= ~CBAUDEX;

@@ -114,9 +114,9 @@ speed_t tty_termios_input_baud_rate(struct ktermios *termios)
cbaud += 15;
return baud_table[cbaud];
+#else /* IBSHIFT */
return tty_termios_baud_rate(termios);
+#endif /* IBSHIFT */

@@ -156,10 +156,11 @@ void tty_termios_encode_baud_rate(struct ktermios *termios,
termios->c_ispeed = ibaud;
termios->c_ospeed = obaud;

-#ifdef BOTHER
+#ifdef IBSHIFT
if ((termios->c_cflag >> IBSHIFT) & CBAUD)
ibinput = 1; /* An input speed was specified */
+#ifdef BOTHER
/* If the user asked for a precise weird speed give a precise weird
answer. If they asked for a Bfoo speed they may have problems
digesting non-exact replies so fuzz a bit */
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