Commit eff6937a authored Jan 02, 2009 by Alan Cox Committed by Linus Torvalds Jan 02, 2009

tty: USB tty devices can block in tcdrain when unplugged



The underlying problem is that the device methods don't all correctly
handle disconnected status and some keep reporting bytes pending which
causes tcdrain to stall.

When the cable is unplugged they are definitely gone, and as this is true
for all USB cables we can fix it in the core usb serial code.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 39aced68

drivers/usb/serial/usb-serial.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -339,6 +339,10 @@ static int serial_chars_in_buffer(struct tty_struct *tty)
		dbg("%s = port %d", __func__, port->number);

		WARN_ON(!port->port.count);
		/* if the device was unplugged then any remaining characters
		fell out of the connector ;) */
		if (port->serial->disconnected)
		return 0;
		/* pass on to the driver specific version of this function */
		return port->serial->type->chars_in_buffer(tty);
		}