commit ef4ea0e9627372570934f2e6472cf1cc8c8e1c7c
Author: Sepherosa Ziehau <sephe@dragonflybsd.org>
Date:   Fri Aug 4 14:22:17 2017 +0800

    mlx4: Log max MTU

diff --git a/sys/dev/mlx4/mlx4_en/mlx4_en_netdev.c b/sys/dev/mlx4/mlx4_en/mlx4_en_netdev.c
index f3b36170fef..bc835b8592e 100644
--- a/sys/dev/mlx4/mlx4_en/mlx4_en_netdev.c
+++ b/sys/dev/mlx4/mlx4_en/mlx4_en_netdev.c
@@ -1773,7 +1773,8 @@ static int mlx4_en_change_mtu(struct net_device *dev, int new_mtu)
 	       (unsigned)dev->if_mtu, (unsigned)new_mtu);
 
 	if ((new_mtu < MLX4_EN_MIN_MTU) || (new_mtu > priv->max_mtu)) {
-		en_err(priv, "Bad MTU size:%d.\n", new_mtu);
+		en_err(priv, "Bad MTU size:%d, max %u.\n", new_mtu,
+		    priv->max_mtu);
 		return -EPERM;
 	}
 	mutex_lock(&mdev->state_lock);