usb serial: more fixes and groundwork for tty changes

 - If a termios change fails due to lack of memory we should copy the
   old settings back over as the device has not changed
 - Note various locking problems
 - kl5kusb105 had various remaining tty flag handling problems
 - Make safe_serial use tty_insert_flip_string not open coded loops
 - set termios speed properly in usb_serial

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

16 files changed, 93 insertions, 67 deletions

diff --git a/drivers/usb/serial/ark3116.c b/drivers/usb/serial/ark3116.c
index 9d708b2..599ab2e 100644
--- a/drivers/usb/serial/ark3116.c
+++ b/drivers/usb/serial/ark3116.c
@@ -192,6 +192,7 @@ static void ark3116_set_termios(struct usb_serial_port *port,
 	buf = kmalloc(1, GFP_KERNEL);
 	if (!buf) {
 		dbg("error kmalloc");
+		*port->tty->termios = *old_termios;
 		return;
 	}
 
diff --git a/drivers/usb/serial/cyberjack.c b/drivers/usb/serial/cyberjack.c
index 5348e97..d077534 100644
--- a/drivers/usb/serial/cyberjack.c
+++ b/drivers/usb/serial/cyberjack.c
@@ -151,7 +151,7 @@ static void cyberjack_shutdown (struct usb_serial *serial)
 	
 	dbg("%s", __func__);
 
-	for (i=0; i < serial->num_ports; ++i) {
+	for (i = 0; i < serial->num_ports; ++i) {
 		usb_kill_urb(serial->port[i]->interrupt_in_urb);
 		/* My special items, the standard routines free my urbs */
 		kfree(usb_get_serial_port_data(serial->port[i]));
@@ -209,7 +209,7 @@ static int cyberjack_write (struct usb_serial_port *port, const unsigned char *b
 
 	if (count == 0) {
 		dbg("%s - write request of 0 bytes", __func__);
-		return (0);
+		return 0;
 	}
 
 	spin_lock_bh(&port->lock);
@@ -223,12 +223,12 @@ static int cyberjack_write (struct usb_serial_port *port, const unsigned char *b
 
 	spin_lock_irqsave(&priv->lock, flags);
 
-	if( (count+priv->wrfilled)>sizeof(priv->wrbuf) ) {
+	if( (count+priv->wrfilled) > sizeof(priv->wrbuf) ) {
 		/* To much data for buffer. Reset buffer. */
-		priv->wrfilled=0;
-		spin_unlock_irqrestore(&priv->lock, flags);
+		priv->wrfilled = 0;
 		port->write_urb_busy = 0;
-		return (0);
+		spin_unlock_irqrestore(&priv->lock, flags);
+		return 0;
 	}
 
 	/* Copy data */
@@ -269,8 +269,8 @@ static int cyberjack_write (struct usb_serial_port *port, const unsigned char *b
 		if (result) {
 			err("%s - failed submitting write urb, error %d", __func__, result);
 			/* Throw away data. No better idea what to do with it. */
-			priv->wrfilled=0;
-			priv->wrsent=0;
+			priv->wrfilled = 0;
+			priv->wrsent = 0;
 			spin_unlock_irqrestore(&priv->lock, flags);
 			port->write_urb_busy = 0;
 			return 0;
@@ -282,8 +282,8 @@ static int cyberjack_write (struct usb_serial_port *port, const unsigned char *b
 		if( priv->wrsent>=priv->wrfilled ) {
 			dbg("%s - buffer cleaned", __func__);
 			memset( priv->wrbuf, 0, sizeof(priv->wrbuf) );
-			priv->wrfilled=0;
-			priv->wrsent=0;
+			priv->wrfilled = 0;
+			priv->wrsent = 0;
 		}
 	}
 
@@ -294,6 +294,7 @@ static int cyberjack_write (struct usb_serial_port *port, const unsigned char *b
 
 static int cyberjack_write_room( struct usb_serial_port *port )
 {
+	/* FIXME: .... */
 	return CYBERJACK_LOCAL_BUF_SIZE;
 }
 
@@ -314,7 +315,7 @@ static void cyberjack_read_int_callback( struct urb *urb )
 	usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length, data);
 
 	/* React only to interrupts signaling a bulk_in transfer */
-	if( (urb->actual_length==4) && (data[0]==0x01) ) {
+	if( (urb->actual_length == 4) && (data[0] == 0x01) ) {
 		short old_rdtodo;
 
 		/* This is a announcement of coming bulk_ins. */
@@ -450,8 +451,8 @@ static void cyberjack_write_bulk_callback (struct urb *urb)
 		if (result) {
 			err("%s - failed submitting write urb, error %d", __func__, result);
 			/* Throw away data. No better idea what to do with it. */
-			priv->wrfilled=0;
-			priv->wrsent=0;
+			priv->wrfilled = 0;
+			priv->wrsent = 0;
 			goto exit;
 		}
 
@@ -463,8 +464,8 @@ static void cyberjack_write_bulk_callback (struct urb *urb)
 		if( (priv->wrsent>=priv->wrfilled) || (priv->wrsent>=blksize) ) {
 			dbg("%s - buffer cleaned", __func__);
 			memset( priv->wrbuf, 0, sizeof(priv->wrbuf) );
-			priv->wrfilled=0;
-			priv->wrsent=0;
+			priv->wrfilled = 0;
+			priv->wrsent = 0;
 		}
 	}
 
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 2078667..65765ce 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -262,13 +262,14 @@ int usb_serial_generic_write_room (struct usb_serial_port *port)
 
 	dbg("%s - port %d", __func__, port->number);
 
+	/* FIXME: Locking */
 	if (serial->num_bulk_out) {
 		if (!(port->write_urb_busy))
 			room = port->bulk_out_size;
 	}
 
 	dbg("%s - returns %d", __func__, room);
-	return (room);
+	return room;
 }
 
 int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port)
@@ -278,6 +279,7 @@ int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port)
 
 	dbg("%s - port %d", __func__, port->number);
 
+	/* FIXME: Locking */
 	if (serial->num_bulk_out) {
 		if (port->write_urb_busy)
 			chars = port->write_urb->transfer_buffer_length;
@@ -368,7 +370,6 @@ void usb_serial_generic_write_bulk_callback (struct urb *urb)
 		    __func__, status);
 		return;
 	}
-
 	usb_serial_port_softint(port);
 }
 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
index 857c531..0d122fe 100644
--- a/drivers/usb/serial/keyspan.c
+++ b/drivers/usb/serial/keyspan.c
@@ -1187,6 +1187,7 @@ static int keyspan_write_room (struct usb_serial_port *port)
 	p_priv = usb_get_serial_port_data(port);
 	d_details = p_priv->device_details;
 
+	/* FIXME: locking */
 	if (d_details->msg_format == msg_usa90)
    		data_len = 64;
 	else
@@ -1203,13 +1204,13 @@ static int keyspan_write_room (struct usb_serial_port *port)
 			if (this_urb->status != -EINPROGRESS)
 				return (data_len);
 	}
-	return (0);
+	return 0;
 }
 
 
 static int keyspan_chars_in_buffer (struct usb_serial_port *port)
 {
-	return (0);
+	return 0;
 }
 
 
@@ -1289,7 +1290,7 @@ static int keyspan_open (struct usb_serial_port *port, struct file *filp)
 	//mdelay(100);
 	//keyspan_set_termios(port, NULL);
 
-	return (0);
+	return 0;
 }
 
 static inline void stop_urb(struct urb *urb)
@@ -2006,7 +2007,7 @@ static int keyspan_usa26_send_setup(struct usb_serial *serial,
 	}
 #endif
 
-	return (0);
+	return 0;
 }
 
 static int keyspan_usa28_send_setup(struct usb_serial *serial,
@@ -2131,7 +2132,7 @@ static int keyspan_usa28_send_setup(struct usb_serial *serial,
 	}
 #endif
 
-	return (0);
+	return 0;
 }
 
 static int keyspan_usa49_send_setup(struct usb_serial *serial,
@@ -2317,7 +2318,7 @@ static int keyspan_usa49_send_setup(struct usb_serial *serial,
 	}
 #endif
 
-	return (0);
+	return 0;
 }
 
 static int keyspan_usa90_send_setup(struct usb_serial *serial,
@@ -2455,7 +2456,7 @@ static int keyspan_usa90_send_setup(struct usb_serial *serial,
 	if ((err = usb_submit_urb(this_urb, GFP_ATOMIC)) != 0) {
 		dbg("%s - usb_submit_urb(setup) failed (%d)", __func__, err);
 	}
-	return (0);
+	return 0;
 }
 
 static int keyspan_usa67_send_setup(struct usb_serial *serial,
@@ -2603,7 +2604,7 @@ static int keyspan_usa67_send_setup(struct usb_serial *serial,
 	if (err != 0)
 		dbg("%s - usb_submit_urb(setup) failed (%d)", __func__,
 				err);
-	return (0);
+	return 0;
 }
 
 static void keyspan_send_setup(struct usb_serial_port *port, int reset_port)
@@ -2696,7 +2697,7 @@ static int keyspan_startup (struct usb_serial *serial)
 				err);
 	}
 			
-	return (0);
+	return 0;
 }
 
 static void keyspan_shutdown (struct usb_serial *serial)
diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index 6ce292e..b650fb4 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -636,14 +636,19 @@ static int keyspan_pda_write_room (struct usb_serial_port *port)
 static int keyspan_pda_chars_in_buffer (struct usb_serial_port *port)
 {
 	struct keyspan_pda_private *priv;
+	unsigned long flags;
+	int ret = 0;
 
 	priv = usb_get_serial_port_data(port);
 
 	/* when throttled, return at least WAKEUP_CHARS to tell select() (via
 	   n_tty.c:normal_poll() ) that we're not writeable. */
+
+	spin_lock_irqsave(&port->lock, flags);
 	if (port->write_urb_busy || priv->tx_throttled)
-		return 256;
-	return 0;
+		ret = 256;
+	spin_unlock_irqrestore(&port->lock, flags);
+	return ret;
 }
 
 
diff --git a/drivers/usb/serial/kl5kusb105.c b/drivers/usb/serial/kl5kusb105.c
index 160e192..b3ac045 100644
--- a/drivers/usb/serial/kl5kusb105.c
+++ b/drivers/usb/serial/kl5kusb105.c
@@ -702,12 +702,14 @@ static void klsi_105_set_termios (struct usb_serial_port *port,
 				  struct ktermios *old_termios)
 {
 	struct klsi_105_private *priv = usb_get_serial_port_data(port);
-	unsigned int iflag = port->tty->termios->c_iflag;
+	struct tty_struct *tty = port->tty;
+	unsigned int iflag = tty->termios->c_iflag;
 	unsigned int old_iflag = old_termios->c_iflag;
-	unsigned int cflag = port->tty->termios->c_cflag;
+	unsigned int cflag = tty->termios->c_cflag;
 	unsigned int old_cflag = old_termios->c_cflag;
 	struct klsi_105_port_settings cfg;
 	unsigned long flags;
+	speed_t baud;
 	
 	/* lock while we are modifying the settings */
 	spin_lock_irqsave (&priv->lock, flags);
@@ -715,6 +717,8 @@ static void klsi_105_set_termios (struct usb_serial_port *port,
 	/*
 	 * Update baud rate
 	 */
+	baud = tty_get_baud_rate(tty);
+
 	if( (cflag & CBAUD) != (old_cflag & CBAUD) ) {
 	        /* reassert DTR and (maybe) RTS on transition from B0 */
 		if( (old_cflag & CBAUD) == B0 ) {
@@ -728,8 +732,8 @@ static void klsi_105_set_termios (struct usb_serial_port *port,
 			mct_u232_set_modem_ctrl(serial, priv->control_state);
 #endif
 		}
-		
-		switch(tty_get_baud_rate(port->tty)) {
+	}
+	switch(baud) {
 		case 0: /* handled below */
 			break;
 		case 1200:
@@ -757,25 +761,26 @@ static void klsi_105_set_termios (struct usb_serial_port *port,
 			priv->cfg.baudrate = kl5kusb105a_sio_b115200;
 			break;
 		default:
-			err("KLSI USB->Serial converter:"
+			dbg("KLSI USB->Serial converter:"
 			    " unsupported baudrate request, using default"
 			    " of 9600");
 			priv->cfg.baudrate = kl5kusb105a_sio_b9600;
+			baud = 9600;
 			break;
-		}
-		if ((cflag & CBAUD) == B0 ) {
-			dbg("%s: baud is B0", __func__);
-			/* Drop RTS and DTR */
-			/* maybe this should be simulated by sending read
-			 * disable and read enable messages?
-			 */
-			;
+	}
+	if ((cflag & CBAUD) == B0 ) {
+		dbg("%s: baud is B0", __func__);
+		/* Drop RTS and DTR */
+		/* maybe this should be simulated by sending read
+		 * disable and read enable messages?
+		 */
+		;
 #if 0
-			priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
-        		mct_u232_set_modem_ctrl(serial, priv->control_state);
+		priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
+       		mct_u232_set_modem_ctrl(serial, priv->control_state);
 #endif
-		}
 	}
+	tty_encode_baud_rate(tty, baud, baud);
 
 	if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
 		/* set the number of data bits */
@@ -807,6 +812,8 @@ static void klsi_105_set_termios (struct usb_serial_port *port,
 	if ((cflag & (PARENB|PARODD)) != (old_cflag & (PARENB|PARODD))
 	    || (cflag & CSTOPB) != (old_cflag & CSTOPB) ) {
 		
+		/* Not currently supported */
+		tty->termios->c_cflag &= ~(PARENB|PARODD|CSTOPB);
 #if 0
 		priv->last_lcr = 0;
 
@@ -834,6 +841,8 @@ static void klsi_105_set_termios (struct usb_serial_port *port,
 	    || (iflag & IXON) != (old_iflag & IXON)
 	    ||  (cflag & CRTSCTS) != (old_cflag & CRTSCTS) ) {
 		
+		/* Not currently supported */
+		tty->termios->c_cflag &= ~CRTSCTS;
 		/* Drop DTR/RTS if no flow control otherwise assert */
 #if 0
 		if ((iflag & IXOFF) || (iflag & IXON) || (cflag & CRTSCTS) )
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index 74b889b..50f1fe2 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -635,6 +635,7 @@ static int mos7720_write_room(struct usb_serial_port *port)
 		return -ENODEV;
 	}
 
+	/* FIXME: Locking */
 	for (i = 0; i < NUM_URBS; ++i) {
 		if (mos7720_port->write_urb_pool[i] && mos7720_port->write_urb_pool[i]->status != -EINPROGRESS)
 			room += URB_TRANSFER_BUFFER_SIZE;
diff --git a/drivers/usb/serial/navman.c b/drivers/usb/serial/navman.c
index 7cea325..43c8894 100644
--- a/drivers/usb/serial/navman.c
+++ b/drivers/usb/serial/navman.c
@@ -6,6 +6,10 @@
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License
  *	version 2 as published by the Free Software Foundation.
+ *
+ * TODO:
+ *	Add termios method that uses copy_hw but also kills all echo
+ *	flags as the navman is rx only so cannot echo.
  */
 
 #include <linux/kernel.h>
@@ -106,12 +110,8 @@ static int navman_write(struct usb_serial_port *port,
 
 	/*
 	 * This device can't write any data, only read from the device
-	 * so we just silently eat all data sent to us and say it was
-	 * successfully sent.
-	 * Evil, I know, but do you have a better idea?
 	 */
-
-	return count;
+	return -EOPNOTSUPP;
 }
 
 static struct usb_serial_driver navman_device = {
diff --git a/drivers/usb/serial/omninet.c b/drivers/usb/serial/omninet.c
index 1b041c5..10090cb 100644
--- a/drivers/usb/serial/omninet.c
+++ b/drivers/usb/serial/omninet.c
@@ -295,8 +295,9 @@ static int omninet_write_room (struct usb_serial_port *port)
 	struct usb_serial 	*serial = port->serial;
 	struct usb_serial_port 	*wport 	= serial->port[1];
 
-	int room = 0; // Default: no room
+	int room = 0; /* Default: no room */
 
+	/* FIXME: no consistent locking for write_urb_busy */
 	if (wport->write_urb_busy)
 		room = wport->bulk_out_size - OMNINET_HEADERLEN;
 
diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 9202418..a838926 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -656,6 +656,7 @@ static int option_write_room(struct usb_serial_port *port)
 
 	portdata = usb_get_serial_port_data(port);
 
+
 	for (i=0; i < N_OUT_URB; i++) {
 		this_urb = portdata->out_urbs[i];
 		if (this_urb && !test_bit(i, &portdata->out_busy))
@@ -677,6 +678,8 @@ static int option_chars_in_buffer(struct usb_serial_port *port)
 
 	for (i=0; i < N_OUT_URB; i++) {
 		this_urb = portdata->out_urbs[i];
+		/* FIXME: This locking is insufficient as this_urb may
+		   go unused during the test */
 		if (this_urb && test_bit(i, &portdata->out_busy))
 			data_len += this_urb->transfer_buffer_length;
 	}
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 2b4ab37..c60930e 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -546,6 +546,8 @@ static void pl2303_set_termios(struct usb_serial_port *port,
 	buf = kzalloc(7, GFP_KERNEL);
 	if (!buf) {
 		dev_err(&port->dev, "%s - out of memory.\n", __func__);
+		/* Report back no change occurred */
+		*port->tty->termios = *old_termios;
 		return;
 	}
 
diff --git a/drivers/usb/serial/safe_serial.c b/drivers/usb/serial/safe_serial.c
index 3fe98a5..e6acac4 100644
--- a/drivers/usb/serial/safe_serial.c
+++ b/drivers/usb/serial/safe_serial.c
@@ -198,7 +198,6 @@ static void safe_read_bulk_callback (struct urb *urb)
 	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 	unsigned char *data = urb->transfer_buffer;
 	unsigned char length = urb->actual_length;
-	int i;
 	int result;
 	int status = urb->status;
 
@@ -227,16 +226,10 @@ static void safe_read_bulk_callback (struct urb *urb)
 	if (safe) {
 		__u16 fcs;
 		if (!(fcs = fcs_compute10 (data, length, CRC10_INITFCS))) {
-
 			int actual_length = data[length - 2] >> 2;
-
 			if (actual_length <= (length - 2)) {
-
 				info ("%s - actual: %d", __func__, actual_length);
-
-				for (i = 0; i < actual_length; i++) {
-					tty_insert_flip_char (port->tty, data[i], 0);
-				}
+				tty_insert_flip_string(port->tty, data, actual_length);
 				tty_flip_buffer_push (port->tty);
 			} else {
 				err ("%s - inconsistent lengths %d:%d", __func__,
@@ -246,9 +239,7 @@ static void safe_read_bulk_callback (struct urb *urb)
 			err ("%s - bad CRC %x", __func__, fcs);
 		}
 	} else {
-		for (i = 0; i < length; i++) {
-			tty_insert_flip_char (port->tty, data[i], 0);
-		}
+		tty_insert_flip_string(port->tty, data, length);
 		tty_flip_buffer_push (port->tty);
 	}
 
@@ -260,6 +251,7 @@ static void safe_read_bulk_callback (struct urb *urb)
 
 	if ((result = usb_submit_urb (urb, GFP_ATOMIC))) {
 		err ("%s - failed resubmitting read urb, error %d", __func__, result);
+		/* FIXME: Need a mechanism to retry later if this happens */
 	}
 }
 
@@ -275,7 +267,7 @@ static int safe_write (struct usb_serial_port *port, const unsigned char *buf, i
 
 	if (!port->write_urb) {
 		dbg ("%s - write urb NULL", __func__);
-		return (0);
+		return 0;
 	}
 
 	dbg ("safe_write write_urb: %d transfer_buffer_length",
@@ -283,11 +275,11 @@ static int safe_write (struct usb_serial_port *port, const unsigned char *buf, i
 
 	if (!port->write_urb->transfer_buffer_length) {
 		dbg ("%s - write urb transfer_buffer_length zero", __func__);
-		return (0);
+		return 0;
 	}
 	if (count == 0) {
 		dbg ("%s - write request of 0 bytes", __func__);
-		return (0);
+		return 0;
 	}
 	spin_lock_bh(&port->lock);
 	if (port->write_urb_busy) {
@@ -359,18 +351,21 @@ static int safe_write (struct usb_serial_port *port, const unsigned char *buf, i
 
 static int safe_write_room (struct usb_serial_port *port)
 {
-	int room = 0;		// Default: no room
+	int room = 0;		/* Default: no room */
+	unsigned long flags;
 
 	dbg ("%s", __func__);
 
+	spin_lock_irqsave(&port->lock, flags);
 	if (port->write_urb_busy)
 		room = port->bulk_out_size - (safe ? 2 : 0);
+	spin_unlock_irqrestore(&port->lock, flags);
 
 	if (room) {
 		dbg ("safe_write_room returns %d", room);
 	}
 
-	return (room);
+	return room;
 }
 
 static int safe_startup (struct usb_serial *serial)
diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index ed30ade..2318887 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -566,6 +566,8 @@ static int sierra_chars_in_buffer(struct usb_serial_port *port)
 	 * have sent out, but hasn't made it through to the
 	 * device as we can't see the backend here, so just
 	 * tell the tty layer that everything is flushed.
+	 *
+	 * FIXME: should walk the outstanding urbs info
 	 */
 	return 0;
 }
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index baf953d..a9934a3 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1179,6 +1179,8 @@ static int __init usb_serial_init(void)
 	usb_serial_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 	usb_serial_tty_driver->init_termios = tty_std_termios;
 	usb_serial_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+	usb_serial_tty_driver->init_termios.c_ispeed = 9600;
+	usb_serial_tty_driver->init_termios.c_ospeed = 9600;
 	tty_set_operations(usb_serial_tty_driver, &serial_ops);
 	result = tty_register_driver(usb_serial_tty_driver);
 	if (result) {
diff --git a/drivers/usb/serial/visor.c b/drivers/usb/serial/visor.c
index 137df44..a100a52 100644
--- a/drivers/usb/serial/visor.c
+++ b/drivers/usb/serial/visor.c
@@ -469,6 +469,8 @@ static int visor_chars_in_buffer (struct usb_serial_port *port)
 	 * have sent out, but hasn't made it through to the
 	 * device, so just tell the tty layer that everything
 	 * is flushed.
+	 *
+	 * FIXME: Should walk outstanding_urbs
 	 */
 	return 0;
 }
diff --git a/drivers/usb/serial/whiteheat.c b/drivers/usb/serial/whiteheat.c
index fb02424..6926a81 100644
--- a/drivers/usb/serial/whiteheat.c
+++ b/drivers/usb/serial/whiteheat.c
@@ -219,7 +219,7 @@ struct whiteheat_urb_wrap {
 struct whiteheat_private {
 	spinlock_t		lock;
 	__u8			flags;
-	__u8			mcr;
+	__u8			mcr;		/* FIXME: no locking on mcr */
 	struct list_head	rx_urbs_free;
 	struct list_head	rx_urbs_submitted;
 	struct list_head	rx_urb_q;