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| author | Johan Hovold <johan@kernel.org> | 2018-07-15 16:39:34 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-26 09:38:11 +0300 |
| commit | 3c11fe1edaff491fd43fc9270282e04981621d99 (patch) | |
| tree | b60a401e95c48e64a1ba78f63ec0a8dcf11fa334 /drivers/tty/tty_baudrate.c | |
| parent | ed3151e4221452a77305e28ba1728db84bc08429 (diff) | |
| download | linux-3c11fe1edaff491fd43fc9270282e04981621d99.tar.xz | |
tty: fix termios input-speed encoding when using BOTHER
[ Upstream commit 1cee38f0363a88db374e50b232ca17b9a4c12fa0 ]
When the termios CIBAUD bits are left unset (i.e. B0), we use the same
output and input speed and should leave CIBAUD unchanged.
When the user requests a rate using BOTHER and c_ospeed which the driver
cannot set exactly, the driver can report back the actual baud rate
using tty_termios_encode_baud_rate(). If this rate is close enough to a
standard rate however, we could end up setting CIBAUD to a Bfoo value
despite the user having left it unset.
This in turn could lead to an unexpected input rate being set on
subsequent termios updates.
Fix this by using a zero tolerance value also for the input rate when
CIBAUD is clear so that the matching logic works as expected.
Fixes: 78137e3b34e1 ("[PATCH] tty: improve encode_baud_rate logic")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_baudrate.c')
| -rw-r--r-- | drivers/tty/tty_baudrate.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/tty/tty_baudrate.c b/drivers/tty/tty_baudrate.c index 5c33fd25676d..8457bb941e1a 100644 --- a/drivers/tty/tty_baudrate.c +++ b/drivers/tty/tty_baudrate.c @@ -156,16 +156,20 @@ void tty_termios_encode_baud_rate(struct ktermios *termios, termios->c_ospeed = obaud; #ifdef BOTHER + if ((termios->c_cflag >> IBSHIFT) & CBAUD) + ibinput = 1; /* An input speed was specified */ + /* 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 */ - if ((termios->c_cflag & CBAUD) == BOTHER) + if ((termios->c_cflag & CBAUD) == BOTHER) { oclose = 0; + if (!ibinput) + iclose = 0; + } if (((termios->c_cflag >> IBSHIFT) & CBAUD) == BOTHER) iclose = 0; - if ((termios->c_cflag >> IBSHIFT) & CBAUD) - ibinput = 1; /* An input speed was specified */ #endif termios->c_cflag &= ~CBAUD; |