USB: ftdi_sio: fix status line change handling for TIOCMIWAIT and TIOCGICOUNT

[linux-flexiantxendom0.git] / drivers / usb / serial / ftdi_sio.c

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index f2c9ef7..cfc8e59 100644 (file)
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -75,7 +75,7 @@ struct ftdi_private {
        unsigned long last_dtr_rts;     /* saved modem control outputs */
        struct async_icount     icount;
        wait_queue_head_t delta_msr_wait; /* Used for TIOCMIWAIT */
-       char prev_status, diff_status;        /* Used for TIOCMIWAIT */
+       char prev_status;        /* Used for TIOCMIWAIT */
        char transmit_empty;    /* If transmitter is empty or not */
        struct usb_serial_port *port;
        __u16 interface;        /* FT2232C, FT2232H or FT4232H port interface
@@ -1979,17 +1979,19 @@ static int ftdi_process_packet(struct tty_struct *tty,
           N.B. packet may be processed more than once, but differences
           are only processed once.  */
        status = packet[0] & FTDI_STATUS_B0_MASK;
-       if (status & FTDI_RS0_CTS)
-               priv->icount.cts++;
-       if (status & FTDI_RS0_DSR)
-               priv->icount.dsr++;
-       if (status & FTDI_RS0_RI)
-               priv->icount.rng++;
-       if (status & FTDI_RS0_RLSD)
-               priv->icount.dcd++;
        if (status != priv->prev_status) {
-               priv->diff_status |= status ^ priv->prev_status;
-               wake_up_interruptible(&priv->delta_msr_wait);
+               char diff_status = status ^ priv->prev_status;
+
+               if (diff_status & FTDI_RS0_CTS)
+                       priv->icount.cts++;
+               if (diff_status & FTDI_RS0_DSR)
+                       priv->icount.dsr++;
+               if (diff_status & FTDI_RS0_RI)
+                       priv->icount.rng++;
+               if (diff_status & FTDI_RS0_RLSD)
+                       priv->icount.dcd++;
+
+               wake_up_interruptible_all(&priv->delta_msr_wait);
                priv->prev_status = status;
        }