From: Alan Cox <alan@linux.intel.com>
Date: Wed, 28 Oct 2009 20:12:32 +0000 (+0100)
Subject: tty_port: If we are opened non blocking we still need to raise the carrier
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4175f3e31cc7157669aa66d46dc79de6ae0126ce;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

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 <alan@linux.intel.com>
Reported-by: Karl Hiramoto <karl@hiramoto.org>
Tested-by:  Karl Hiramoto <karl@hiramoto.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

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;
 	}