From 4175f3e31cc7157669aa66d46dc79de6ae0126ce Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 28 Oct 2009 21:12:32 +0100 Subject: [PATCH] tty_port: If we are opened non blocking we still need to raise the carrier Original discussion: http://thread.gmane.org/gmane.linux.usb.general/23217/focus=23248 or http://marc.info/?l=linux-usb&m=125553790714133&w=2 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 Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/char/tty_port.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c index a4bbb28f10be..2e8552dc5eda 100644 --- a/drivers/char/tty_port.c +++ b/drivers/char/tty_port.c @@ -221,6 +221,9 @@ int tty_port_block_til_ready(struct tty_port *port, 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; } -- 2.39.2