[lkml]   [2009]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[039/119] tty_port: If we are opened non blocking we still need to raise the carrier
2.6.31-stable review patch.  If anyone has any objections, please let us know.

From: Alan Cox <>

commit 4175f3e31cc7157669aa66d46dc79de6ae0126ce upstream.

Original discussion:

The tty_port code inherited a bug common to various drivers it was based
upon. If the tty is opened O_NONBLOCK we do not wait for the carrier to be
raised but we must still raise our modem lines if appropriate.

(There is a second question here about whether we should do so if CLOCAL is
set but that can wait)

Signed-off-by: Alan Cox <>
Reported-by: Karl Hiramoto <>
Tested-by: Karl Hiramoto <>
Signed-off-by: Greg Kroah-Hartman <>

drivers/char/tty_port.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -219,6 +219,9 @@ int tty_port_block_til_ready(struct tty_
the port has just hung up or is in another error state */
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
+ /* Indicate we are open */
+ if (tty->termios->c_cflag & CBAUD)
+ tty_port_raise_dtr_rts(port);
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;

 \ /
  Last update: 2009-12-07 01:19    [W:0.273 / U:2.384 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site