diff --git a/drivers/net/ethernet/micrel/ks8851_common.c b/drivers/net/ethernet/micrel/ks8851_common.c
index 13462811eaae..7fa1820db9cc 100644
--- a/drivers/net/ethernet/micrel/ks8851_common.c
+++ b/drivers/net/ethernet/micrel/ks8851_common.c
@@ -482,6 +482,7 @@ static int ks8851_net_open(struct net_device *dev)
 	ks8851_wrreg16(ks, KS_IER, ks->rc_ier);
 
 	ks->queued_len = 0;
+	ks->tx_space = ks8851_rdreg16(ks, KS_TXMIR);
 	netif_start_queue(ks->netdev);
 
 	netif_dbg(ks, ifup, ks->netdev, "network device up\n");
@@ -1101,7 +1102,6 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev,
 	int ret;
 
 	ks->netdev = netdev;
-	ks->tx_space = 6144;
 
 	ks->gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 	ret = PTR_ERR_OR_ZERO(ks->gpio);