From 030ee7ae52a46a2be52ccc8242c4a330aba8d38e Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Fri, 6 Jan 2017 19:15:12 +0100 Subject: 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: 664d5df92e88 ("USB: usb-serial ch341: support for DTR/RTS/CTS") Cc: stable Signed-off-by: Johan Hovold --- drivers/usb/serial/ch341.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'drivers/usb/serial') diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index 6279df905c14..0cc5056b304d 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -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); - priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); - spin_unlock_irqrestore(&priv->lock, flags); } - ch341_set_handshake(port->serial->dev, priv->line_control); + 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) -- cgit v1.2.3