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| author | Wang YanQing <udknight@gmail.com> | 2013-05-09 14:16:47 +0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-05-30 14:35:04 +0100 |
| commit | 40a2e8cd0cb2548bb78a8b8b3ace6b911f2bb98b (patch) | |
| tree | 136f6981134d05aa47a657d4758f82de92e30998 | |
| parent | e75b61897276c5100e61c9c74fd55ded28f31431 (diff) | |
| download | lwn-40a2e8cd0cb2548bb78a8b8b3ace6b911f2bb98b.tar.gz lwn-40a2e8cd0cb2548bb78a8b8b3ace6b911f2bb98b.zip | |
TTY: Fix tty miss restart after we turn off flow-control
commit dab73b4eb9ef924a2b90dab84e539076d82b256f upstream.
I meet emacs hang in start if I do the operation below:
1: echo 3 > /proc/sys/vm/drop_caches
2: emacs BigFile
3: Press CTRL-S follow 2 immediately
Then emacs hang on, CTRL-Q can't resume, the terminal
hang on, you can do nothing with this terminal except
close it.
The reason is before emacs takeover control the tty,
we use CTRL-S to XOFF it. Then when emacs takeover the
control, it may don't use the flow-control, so emacs hang.
This patch fix it.
This patch will fix a kind of strange tty relation hang problem,
I believe I meet it with vim in ssh, and also see below bug report:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=465823
Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | drivers/tty/n_tty.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 8481aaee2f1a..0f8a785a5f60 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1530,6 +1530,14 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) tty->real_raw = 0; } n_tty_set_room(tty); + /* + * Fix tty hang when I_IXON(tty) is cleared, but the tty + * been stopped by STOP_CHAR(tty) before it. + */ + if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) { + start_tty(tty); + } + /* The termios change make the tty ready for I/O */ wake_up_interruptible(&tty->write_wait); wake_up_interruptible(&tty->read_wait); |