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Commit 2feb633d authored by Richard Ash's avatar Richard Ash Committed by Greg Kroah-Hartman
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Staging: quatech_usb2: chars_in_buffer() fix 



It seems I can't count.

Patch to fix chars_in_buffer() method (broken in vendor driver), and
subsequently simplify the close() method, making it somewhat less
broken. There is quite a bit more improvement to do on this method
though.

Signed-off-by: default avatarRichard Ash <richard@audacityteam.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent dbe24815

drivers/staging/quatech_usb2/quatech_usb2.c

+12 −29
Original line number Diff line number Diff line
@@ -619,7 +619,10 @@ int qt2_open(struct tty_struct *tty, struct usb_serial_port *port) 
	return 0;

}



/* called when a port is closed by userspace */

/* called when a port is closed by userspace. It won't be called, however,

 * until calls to chars_in_buffer() reveal that the port has completed

 * sending buffered data, and there is nothing else to do. Thus we don't have

 * to rely on forcing data through in this function. */

/* Setting close_pending should keep new data from being written out,

 * once all the data in the enpoint buffers is moved out we won't get

 * any more. */
@@ -644,26 +647,8 @@ static void qt2_close(struct usb_serial_port *port) 
	/* get the device private data */

	port_extra = qt2_get_port_private(port); /* port private data */



	/* to check we have successfully flushed the buffers on the hardware,

	 * we set the flags indicating flushes have occured to false, then ask

	 * for flushes to occur, then sit in a timed loop until either we

	 * get notified back that the flushes have happened (good) or we get

	 * tired of waiting for the flush to happen and give up (bad).

	 */

	port_extra->rcv_flush = false;

	port_extra->xmit_flush = false;

	qt2_box_flush(serial, port->number, QT2_FLUSH_TX); /* flush tx buffer */

	qt2_box_flush(serial, port->number, QT2_FLUSH_RX); /* flush rx buffer */

	/* now wait for the flags to magically go back to being true */

	jift = jiffies + (10 * HZ);

	do {

		if ((port_extra->rcv_flush == true) &&

			(port_extra->xmit_flush == true)) {

			dbg("Flush completed");

			break;

		}

		schedule();

	} while (jiffies <= jift);

	/* we don't need to force flush though the hardware, so we skip using

	 * qt2_box_flush() here */



	/* we can now (and only now) stop reading data */

	port_extra->close_pending = true;
@@ -672,6 +657,9 @@ static void qt2_close(struct usb_serial_port *port) 
	 * still be pushing characters out over the line, so we have to

	 * wait testing the actual line status until the lines change

	 * indicating that the data is done transfering. */

	/* FIXME: slow this polling down so it doesn't run the USB bus flat out

	 * if it actually has to spend any time in this loop (which it normally

	 * doesn't because the buffer is nearly empty) */

	jift = jiffies + (10 * HZ);	/* 10 sec timeout */

	do {

		status = qt2_box_get_register(serial, port->number,
@@ -848,16 +836,12 @@ static int qt2_chars_in_buffer(struct tty_struct *tty) 
{

	struct usb_serial_port *port = tty->driver_data;

	/* parent usb_serial_port pointer */

	int chars = 0;

	struct quatech2_port *port_extra;	/* extra data for this port */

	port_extra = qt2_get_port_private(port);



	dbg("%s(): port %d", __func__, port->number);

	if ((port->write_urb->status == -EINPROGRESS) &&

			(port_extra->tx_pending_bytes != 0))

		chars = port->write_urb->transfer_buffer_length;

	dbg("%s(): returns %d", __func__, chars);

	return chars;

	dbg("%s(): port %d: chars_in_buffer = %d", __func__,

		port->number, port_extra->tx_pending_bytes);

	return port_extra->tx_pending_bytes;

}



/* called when userspace does an ioctl() on the device. Note that
@@ -879,7 +863,6 @@ static int qt2_ioctl(struct tty_struct *tty, struct file *file, 
	/* Declare a wait queue named "wait" */



	unsigned int value;

	int status;

	unsigned int UartNumber;



	if (serial == NULL)