From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: [PATCH v3 2/6] n_tty: Fix throttle for canon lines > 3967 chars Date: Fri, 16 Jan 2015 15:05:35 -0500 Message-ID: <1421438739-29672-3-git-send-email-peter@hurleysoftware.com> References: <1421113668-20468-1-git-send-email-peter@hurleysoftware.com> <1421438739-29672-1-git-send-email-peter@hurleysoftware.com> Return-path: In-Reply-To: <1421438739-29672-1-git-send-email-peter@hurleysoftware.com> Sender: linux-kernel-owner@vger.kernel.org To: Greg Kroah-Hartman Cc: Jiri Slaby , Christian Riesch , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Denis Du , =?UTF-8?q?M=C3=A5ns=20Rullg=C3=A5rd?= , Peter Hurley List-Id: linux-serial@vger.kernel.org The tty driver will be mistakenly throttled if a line termination has not been received, and the line exceeds 3967 chars. Thus, it is possible for the driver to stop sending when it has not yet sent the newline. This does not apply to the pty driver. Don't throttle until at least one line termination has been received. Signed-off-by: Peter Hurley --- drivers/tty/n_tty.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index b60b043..d4b14c3 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -247,6 +247,8 @@ static void n_tty_write_wakeup(struct tty_struct *tty) static void n_tty_check_throttle(struct tty_struct *tty) { + struct n_tty_data *ldata = tty->disc_data; + if (tty->driver->type == TTY_DRIVER_TYPE_PTY) return; /* @@ -254,6 +256,9 @@ static void n_tty_check_throttle(struct tty_struct *tty) * mode. We don't want to throttle the driver if we're in * canonical mode and don't have a newline yet! */ + if (ldata->icanon && ldata->canon_head == ldata->read_tail) + return; + while (1) { int throttled; tty_set_flow_change(tty, TTY_THROTTLE_SAFE); -- 2.2.2