module_param_named(pattern, mod_pattern, uint, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(mod_pattern, "i/o pattern (0 == zeroes)");
 
-static inline void simple_fill_buf(struct urb *urb)
+static unsigned get_maxpacket(struct usb_device *udev, int pipe)
+{
+       struct usb_host_endpoint        *ep;
+
+       ep = usb_pipe_endpoint(udev, pipe);
+       return le16_to_cpup(&ep->desc.wMaxPacketSize);
+}
+
+static void simple_fill_buf(struct urb *urb)
 {
        unsigned        i;
        u8              *buf = urb->transfer_buffer;
        unsigned        len = urb->transfer_buffer_length;
+       unsigned        maxpacket;
 
        switch (pattern) {
        default:
                memset(buf, 0, len);
                break;
        case 1:                 /* mod63 */
+               maxpacket = get_maxpacket(urb->dev, urb->pipe);
                for (i = 0; i < len; i++)
-                       *buf++ = (u8) (i % 63);
+                       *buf++ = (u8) ((i % maxpacket) % 63);
                break;
        }
 }
        u8              expected;
        u8              *buf = urb->transfer_buffer;
        unsigned        len = urb->actual_length;
+       unsigned        maxpacket = get_maxpacket(urb->dev, urb->pipe);
 
        int ret = check_guard_bytes(tdev, urb);
        if (ret)
                 * with set_interface or set_config.
                 */
                case 1:                 /* mod63 */
-                       expected = i % 63;
+                       expected = (i % maxpacket) % 63;
                        break;
                /* always fail unsupported patterns */
                default:
 }
 
 static struct scatterlist *
-alloc_sglist(int nents, int max, int vary)
+alloc_sglist(int nents, int max, int vary, struct usbtest_dev *dev, int pipe)
 {
        struct scatterlist      *sg;
        unsigned                i;
        unsigned                size = max;
+       unsigned                maxpacket =
+               get_maxpacket(interface_to_usbdev(dev->intf), pipe);
 
        if (max == 0)
                return NULL;
                        break;
                case 1:
                        for (j = 0; j < size; j++)
-                               *buf++ = (u8) (j % 63);
+                               *buf++ = (u8) ((j % maxpacket) % 63);
                        break;
                }
 
                        "TEST 5:  write %d sglists %d entries of %d bytes\n",
                                param->iterations,
                                param->sglen, param->length);
-               sg = alloc_sglist(param->sglen, param->length, 0);
+               sg = alloc_sglist(param->sglen, param->length,
+                               0, dev, dev->out_pipe);
                if (!sg) {
                        retval = -ENOMEM;
                        break;
                        "TEST 6:  read %d sglists %d entries of %d bytes\n",
                                param->iterations,
                                param->sglen, param->length);
-               sg = alloc_sglist(param->sglen, param->length, 0);
+               sg = alloc_sglist(param->sglen, param->length,
+                               0, dev, dev->in_pipe);
                if (!sg) {
                        retval = -ENOMEM;
                        break;
                        "TEST 7:  write/%d %d sglists %d entries 0..%d bytes\n",
                                param->vary, param->iterations,
                                param->sglen, param->length);
-               sg = alloc_sglist(param->sglen, param->length, param->vary);
+               sg = alloc_sglist(param->sglen, param->length,
+                               param->vary, dev, dev->out_pipe);
                if (!sg) {
                        retval = -ENOMEM;
                        break;
                        "TEST 8:  read/%d %d sglists %d entries 0..%d bytes\n",
                                param->vary, param->iterations,
                                param->sglen, param->length);
-               sg = alloc_sglist(param->sglen, param->length, param->vary);
+               sg = alloc_sglist(param->sglen, param->length,
+                               param->vary, dev, dev->in_pipe);
                if (!sg) {
                        retval = -ENOMEM;
                        break;