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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: 664d5df92e ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Johan Hovold 2017-01-06 19:15:12 +01:00
parent a20047f36e
commit 030ee7ae52
1 changed files with 7 additions and 9 deletions
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16
drivers/usb/serial/ch341.c
View File

@ -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)