USB: ch341: fix ignored TIOCMIWAIT mask

[firefly-linux-kernel-4.4.55.git] / drivers / usb / serial / ch341.c

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 9dd94a7e08b91efaf03efd22835faa4c156d578f..025b7857a36c33b56e7def9bfd0a0a62aff06915 100644 (file)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -83,7 +83,6 @@ struct ch341_private {
        unsigned baud_rate; /* set baud rate */
        u8 line_control; /* set line control value RTS/DTR */
        u8 line_status; /* active status of modem control inputs */
-       u8 multi_status_change; /* status changed multiple since last call */
 };
 
 static int ch341_control_out(struct usb_device *dev, u8 request,
@@ -174,7 +173,6 @@ static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
                r = 0;
                spin_lock_irqsave(&priv->lock, flags);
                priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
-               priv->multi_status_change = 0;
                spin_unlock_irqrestore(&priv->lock, flags);
        } else
                r = -EPROTO;
@@ -457,10 +455,11 @@ static void ch341_update_line_status(struct usb_serial_port *port,
        spin_lock_irqsave(&priv->lock, flags);
        delta = status ^ priv->line_status;
        priv->line_status = status;
-       if (data[1] & CH341_MULT_STAT)
-               priv->multi_status_change = 1;
        spin_unlock_irqrestore(&priv->lock, flags);
 
+       if (data[1] & CH341_MULT_STAT)
+               dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
+
        if (delta & CH341_BIT_DCD) {
                tty = tty_port_tty_get(&port->port);
                if (tty) {
@@ -516,14 +515,12 @@ static int ch341_tiocmiwait(struct tty_struct *tty, unsigned long arg)
        u8 prevstatus;
        u8 status;
        u8 changed;
-       u8 multi_change = 0;
 
        spin_lock_irqsave(&priv->lock, flags);
        prevstatus = priv->line_status;
-       priv->multi_status_change = 0;
        spin_unlock_irqrestore(&priv->lock, flags);
 
-       while (!multi_change) {
+       for (;;) {
                interruptible_sleep_on(&port->port.delta_msr_wait);
                /* see if a signal did it */
                if (signal_pending(current))
@@ -534,7 +531,6 @@ static int ch341_tiocmiwait(struct tty_struct *tty, unsigned long arg)
 
                spin_lock_irqsave(&priv->lock, flags);
                status = priv->line_status;
-               multi_change = priv->multi_status_change;
                spin_unlock_irqrestore(&priv->lock, flags);
 
                changed = prevstatus ^ status;