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Commit 030ee7ae authored by Johan Hovold's avatar Johan Hovold
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USB: serial: ch341: fix modem-control and B0 handling 



The modem-control signals are managed by the tty-layer during open and
should not be asserted prematurely when set_termios is called from
driver open.

Also make sure that the signals are asserted only when changing speed
from B0.

Fixes: 664d5df9 ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent a20047f3

drivers/usb/serial/ch341.c

+7 −9
Original line number Diff line number Diff line
@@ -384,10 +384,6 @@ static void ch341_set_termios(struct tty_struct *tty, 
		ctrl |= CH341_LCR_STOP_BITS_2;



	if (baud_rate) {

		spin_lock_irqsave(&priv->lock, flags);

		priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);

		spin_unlock_irqrestore(&priv->lock, flags);



		priv->baud_rate = baud_rate;



		r = ch341_init_set_baudrate(port->serial->dev, priv, ctrl);
@@ -395,14 +391,16 @@ static void ch341_set_termios(struct tty_struct *tty, 
			priv->baud_rate = tty_termios_baud_rate(old_termios);

			tty_termios_copy_hw(&tty->termios, old_termios);

		}

	} else {

	}



	spin_lock_irqsave(&priv->lock, flags);

	if (C_BAUD(tty) == B0)

		priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);

	else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)

		priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);

	spin_unlock_irqrestore(&priv->lock, flags);

	}



	ch341_set_handshake(port->serial->dev, priv->line_control);



}



static void ch341_break_ctl(struct tty_struct *tty, int break_state)