From eac2096058fbf1cb7be4ea36ff5b598628ec062d Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
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 <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>
---
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 a4bbb28f10be4..2e8552dc5edae 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;
}
--
2.39.5