Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932082AbbBPIKT (ORCPT ); Mon, 16 Feb 2015 03:10:19 -0500 Received: from victor.provo.novell.com ([137.65.250.26]:41619 "EHLO prv3-mh.provo.novell.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751458AbbBPIKR (ORCPT ); Mon, 16 Feb 2015 03:10:17 -0500 From: Nan Li To: gregkh@linuxfoundation.org, jslaby@suse.cz Cc: linux-kernel@vger.kernel.org, ptesarik@suse.cz, Nan Li Subject: [PATCH 1/1] pty: BREAK for pseudoterminals Date: Fri, 6 Feb 2015 03:11:29 +0800 Message-Id: <1423163489-26538-1-git-send-email-nli@suse.com> X-Mailer: git-send-email 1.7.12.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2000 Lines: 59 This will greatly enhance the usefulness of QEMU virtual serial ports, because the Linux kernel interprets a break on the serial console as a SysRq, but there is currently no way to pass this signal over a pseudo-terminal. This patch will work for transmitting BREAK from master to slave through pseudo-terminal. Signed-off-by: Nan Li --- drivers/tty/pty.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index e72ee62..ac8893a 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -31,6 +31,7 @@ static struct tty_driver *ptm_driver; static struct tty_driver *pts_driver; static DEFINE_MUTEX(devpts_mutex); +#define BREAK_STRING '\0' #endif static void pty_close(struct tty_struct *tty, struct file *filp) @@ -674,6 +675,23 @@ static void pty_unix98_shutdown(struct tty_struct *tty) devpts_kill_index(tty->driver_data, tty->index); } +static int pty_unix98_break_ctl(struct tty_struct *tty, int break_state) +{ + int c; + struct tty_struct *to = tty->link; + + if (break_state) { + /* Stuff the break data into the input queue of the other end */ + c = tty_insert_flip_char(to->port, BREAK_STRING, TTY_BREAK); + /* And shovel */ + if (c) + tty_flip_buffer_push(to->port); + else + return -ENOMEM; + } + return 0; +} + static const struct tty_operations ptm_unix98_ops = { .lookup = ptm_unix98_lookup, .install = pty_unix98_install, @@ -686,6 +704,7 @@ static const struct tty_operations ptm_unix98_ops = { .chars_in_buffer = pty_chars_in_buffer, .unthrottle = pty_unthrottle, .ioctl = pty_unix98_ioctl, + .break_ctl = pty_unix98_break_ctl, .resize = pty_resize, .shutdown = pty_unix98_shutdown, .cleanup = pty_cleanup -- 1.7.12.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/