Commit 4175f3e3 authored Oct 28, 2009 by Alan Cox Committed by Greg Kroah-Hartman Nov 17, 2009

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>

parent ac50e950

drivers/char/tty_port.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}

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