USB: io_ti: query hardware-buffer status in chars_in_buffer

Query hardware-buffer status in chars_in_buffer should the write fifo be
empty.

This is needed to make the tty layer wait for hardware buffers to drain
on close.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index 3abbdaad838d5f892761c940ad09b0d03b1233d3..590f27d3bfc1ec27a808e816883ae0600ad82b51 100644 (file)
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -2088,6 +2088,7 @@ static int edge_chars_in_buffer(struct tty_struct *tty)
        struct edgeport_port *edge_port = usb_get_serial_port_data(port);
        int chars = 0;
        unsigned long flags;
+       int ret;
 
        if (edge_port == NULL)
                return 0;
@@ -2098,6 +2099,12 @@ static int edge_chars_in_buffer(struct tty_struct *tty)
        chars = kfifo_len(&edge_port->write_fifo);
        spin_unlock_irqrestore(&edge_port->ep_lock, flags);
 
+       if (!chars) {
+               ret = tx_active(edge_port);
+               if (ret > 0)
+                       chars = ret;
+       }
+
        dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
        return chars;
 }