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 <udkni...@gmail.com> --- Changes v1-v2: 1: move the fix into n_tty_set_termios instead of change TCXONC's behavior suggested by Peter Hurley 2: rewrite some ChangeLog and use more reasonable subject. Changes v2-v3: 1: Fix potential NULL pointer dereference. drivers/tty/n_tty.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 19083ef..9365978 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1587,6 +1587,14 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) ldata->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); -- 1.7.12.4.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
