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Commit 0dd7a1ae authored by Russell King's avatar Russell King Committed by Russell King
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[PATCH] Serial: Check status of CTS when using flow control 



Fix bugme #4712: read the CTS status and set hw_stopped if CTS
is not active when opening the port and/or enabling CRTSCTS

Thanks to Stefan Wolff for spotting this problem.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent c5f4644e

drivers/serial/serial_core.c

+17 −0
Original line number Original line Diff line number Diff line
@@ -182,6 +182,13 @@ static int uart_startup(struct uart_state *state, int init_hw) 
				uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);

				uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);

		}

		}





		if (info->flags & UIF_CTS_FLOW) {

			spin_lock_irq(&port->lock);

			if (!(port->ops->get_mctrl(port) & TIOCM_CTS))

				info->tty->hw_stopped = 1;

			spin_unlock_irq(&port->lock);

		}



		info->flags |= UIF_INITIALIZED;

		info->flags |= UIF_INITIALIZED;





		clear_bit(TTY_IO_ERROR, &info->tty->flags);

		clear_bit(TTY_IO_ERROR, &info->tty->flags);
@@ -1134,6 +1141,16 @@ static void uart_set_termios(struct tty_struct *tty, struct termios *old_termios 
		spin_unlock_irqrestore(&state->port->lock, flags);

		spin_unlock_irqrestore(&state->port->lock, flags);

	}

	}





	/* Handle turning on CRTSCTS */

	if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {

		spin_lock_irqsave(&state->port->lock, flags);

		if (!(state->port->ops->get_mctrl(state->port) & TIOCM_CTS)) {

			tty->hw_stopped = 1;

			state->port->ops->stop_tx(state->port, 0);

		}

		spin_unlock_irqrestore(&state->port->lock, flags);

	}



#if 0

#if 0

	/*

	/*

	 * No need to wake up processes in open wait, since they

	 * No need to wake up processes in open wait, since they