LKML Archive on
help / color / mirror / Atom feed
From: Marc Zyngier <>
Cc: Allen Yan <>,
	Miquel Raynal <>,
	Gregory CLEMENT <>,
	Greg Kroah-Hartman <>
Subject: [PATCH] serial: mvebu-uart: Fix local flags handling on termios update
Date: Sun, 22 Apr 2018 13:33:46 +0100	[thread overview]
Message-ID: <> (raw)

Commit 68a0db1d7da2 reworked the baud rate selection, but also added
a (not so) subtle change in the way the local flags (c_lflag in the
termios structure) are handled, forcing the new flags to always be the
same as the old ones.

The reason for that particular change is both obscure and undocumented.
It also completely breaks userspace. Something as trivial as getty is

	Debian GNU/Linux 9 sy-borg ttyMV0

	sy-borg login: root

	Debian GNU/Linux 9 sy-borg ttyMV0

which is quite obvious in retrospect: getty cannot get in control of
the echo mode, is stuck in canonical mode, and times out without ever
seeing anything valid. It also begs the question of how this change was
ever tested.

The fix is pretty obvious: stop messing with c_lflag, and the world
will be a happier place.

Cc: # 4.15+
Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate")
Signed-off-by: Marc Zyngier <>
 drivers/tty/serial/mvebu-uart.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 750e5645dc85..f503fab1e268 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -495,7 +495,6 @@ static void mvebu_uart_set_termios(struct uart_port *port,
 		termios->c_iflag |= old->c_iflag & ~(INPCK | IGNPAR);
 		termios->c_cflag &= CREAD | CBAUD;
 		termios->c_cflag |= old->c_cflag & ~(CREAD | CBAUD);
-		termios->c_lflag = old->c_lflag;
 	spin_unlock_irqrestore(&port->lock, flags);

             reply	other threads:[~2018-04-22 12:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-22 12:33 Marc Zyngier [this message]
2018-04-22 15:55 ` Russell King - ARM Linux
2018-04-22 17:07   ` Marc Zyngier
2018-04-22 19:58     ` Russell King - ARM Linux
2018-04-23 15:04       ` Russell King - ARM Linux
2018-04-23 17:39         ` Russell King - ARM Linux

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \
    --subject='Re: [PATCH] serial: mvebu-uart: Fix local flags handling on termios update' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).