- /* refuse mtu that requires the support of scattered packets when this
- * feature has not been enabled before. */
- if (!dev->data->scattered_rx &&
- frame_size > dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM)
+ /*
+ * If device is started, refuse mtu that requires the support of
+ * scattered packets when this feature has not been enabled before.
+ */
+ if (dev->data->dev_started && !dev->data->scattered_rx &&
+ frame_size > dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM) {
+ PMD_INIT_LOG(ERR, "Stop port first.");