Re: [SOLVED] Serial buffer corruption [was Re: FTDI usb-serial possible bug]

[Oliver Neukum <oliver@neukum.org>]

Am Samstag, 5. Mai 2007 20:08 schrieb Antonino Ingargiola:
> Now I don't want to abuse your kindness, but I (personally) would be
> *really* interested in a similar fix for the FTDI usb-serial driver,
> because many measurements I do use an FTDI device.

Does this work?

	Regards
		Oliver
----

--- a/drivers/usb/serial/ftdi_sio.c	2007-05-05 20:21:41.000000000 +0200
+++ b/drivers/usb/serial/ftdi_sio.c	2007-05-05 20:27:09.000000000 +0200
@@ -1749,10 +1749,6 @@ static void ftdi_process_read (struct wo
 			length = 0;
 		}
 
-		if (priv->rx_flags & THROTTLED) {
-			dbg("%s - throttled", __FUNCTION__);
-			break;
-		}
 		if (tty_buffer_request_room(tty, length) < length) {
 			/* break out & wait for throttling/unthrottling to happen */
 			dbg("%s - receive room low", __FUNCTION__);
@@ -1825,16 +1821,6 @@ static void ftdi_process_read (struct wo
 		dbg("%s - incomplete, %d bytes processed, %d remain",
 				__FUNCTION__, packet_offset,
 				urb->actual_length - packet_offset);
-		/* check if we were throttled while processing */
-		spin_lock_irqsave(&priv->rx_lock, flags);
-		if (priv->rx_flags & THROTTLED) {
-			priv->rx_flags |= ACTUALLY_THROTTLED;
-			spin_unlock_irqrestore(&priv->rx_lock, flags);
-			dbg("%s - deferring remainder until unthrottled",
-					__FUNCTION__);
-			return;
-		}
-		spin_unlock_irqrestore(&priv->rx_lock, flags);
 		/* if the port is closed stop trying to read */
 		if (port->open_count > 0){
 			/* delay processing of remainder */
@@ -1856,9 +1842,15 @@ static void ftdi_process_read (struct wo
 			      port->read_urb->transfer_buffer, port->read_urb->transfer_buffer_length,
 			      ftdi_read_bulk_callback, port);
 
-		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
-		if (result)
-			err("%s - failed resubmitting read urb, error %d", __FUNCTION__, result);
+		spin_lock_irqsave(&priv->rx_lock, flags);
+		if (priv->rx_flags & THROTTLED) {
+			priv->rx_flags |= ACTUALLY_THROTTLED;
+		} else {
+			result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+			if (result)
+				err("%s - failed resubmitting read urb, error %d", __FUNCTION__, result);
+		}
+		spin_unlock_irqrestore(&priv->rx_lock, flags);
 	}
 
 	return;