tty_port: If we are opened non blocking we still need to raise the carrier
authorAlan Cox <alan@linux.intel.com>
Wed, 28 Oct 2009 20:12:32 +0000 (21:12 +0100)
committerGreg Kroah-Hartman <gregkh@suse.de>
Tue, 8 Dec 2009 18:21:24 +0000 (10:21 -0800)
commit8f34cea85b340d1057d9251e38d6b000898c659f
treea82bb27ef491c8319e1d22346e33692bad391419
parentffb83b9e7d0e935ccc665ed09f2f7273828c9cfb
tty_port: If we are opened non blocking we still need to raise the carrier

commit 4175f3e31cc7157669aa66d46dc79de6ae0126ce upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/char/tty_port.c