On Fri, Oct 15, 2021 at 07:10:26PM +0200, Alvin Šipraga wrote:

+static struct sk_buff *rtl8_4_tag_xmit(struct sk_buff *skb,
+				       struct net_device *dev)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	__be16 *tag;
+
+	/* Pad out so the (stripped) packet is at least 64 bytes long
+	 * (including FCS), otherwise the switch will drop the packet.
+	 * Then we need an additional 8 bytes for the Realtek tag.
+	 */
+	if (unlikely(__skb_put_padto(skb, ETH_ZLEN + RTL8_4_TAG_LEN, false)))
+		return NULL;

Is this still required if you set rtl8365mb_cpu_rxlen to 64 bytes already?

+
+	skb_push(skb, RTL8_4_TAG_LEN);
+