struct hvc_struct *hp = tty->driver_data;
 
        if (!hp)
-               return -1;
+               return 0;
        return hp->n_outbuf;
 }
 
 
 {
        struct port *port = tty->driver_data;
        struct nozomi *dc = get_dc_by_tty(tty);
-       s32 rval;
+       s32 rval = 0;
 
        if (unlikely(!dc || !port)) {
-               rval = -ENODEV;
                goto exit_in_buffer;
        }
 
        if (unlikely(!port->port.count)) {
                dev_err(&dc->pdev->dev, "No tty open?\n");
-               rval = -ENODEV;
                goto exit_in_buffer;
        }
 
 
        struct ipw_tty *tty = linux_tty->driver_data;
 
        if (!tty)
-               return -ENODEV;
+               return 0;
 
        if (!tty->open_count)
-               return -EINVAL;
+               return 0;
 
        return tty->tx_bytes_queued;
 }
 
        return retval;
 }
 
+/* FIXME: This function does not have error returns */
+
 static int if_chars_in_buffer(struct tty_struct *tty)
 {
        struct cardstate *cs;
 
 {
        struct acm *acm = tty->driver_data;
        if (!ACM_READY(acm))
-               return -EINVAL;
+               return 0;
        /*
         * This is inaccurate (overcounts), but it works.
         */
 
        mos7720_port = usb_get_serial_port_data(port);
        if (mos7720_port == NULL) {
                dbg("%s:leaving ...........", __func__);
-               return -ENODEV;
+               return 0;
        }
 
        for (i = 0; i < NUM_URBS; ++i) {
 
        dbg("%s - port %d", __func__, port->number);
 
        if (tport == NULL)
-               return -ENODEV;
+               return 0;
 
        spin_lock_irqsave(&tport->tp_lock, flags);
        room = ti_buf_space_avail(tport->tp_write_buf);
        dbg("%s - port %d", __func__, port->number);
 
        if (tport == NULL)
-               return -ENODEV;
+               return 0;
 
        spin_lock_irqsave(&tport->tp_lock, flags);
        chars = ti_buf_data_avail(tport->tp_write_buf);