[PATCH net 1/2] r8152: set the RMS of RTL8153 according to the mtu

[Hayes Wang]

Set the received maximum size (RMS) according to the mtu size. It is
unnecessary to receive a packet which is more than the size we could
transmit. Besides, this could let the rx buffer be used effectively.

Signed-off-by: Hayes Wang <hayesw...@realtek.com>
---
 drivers/net/usb/r8152.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 986243c..3a892fa 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -2898,7 +2898,8 @@ static void r8153_first_init(struct r8152 *tp)
 
        rtl_rx_vlan_en(tp, tp->netdev->features & NETIF_F_HW_VLAN_CTAG_RX);
 
-       ocp_write_word(tp, MCU_TYPE_PLA, PLA_RMS, RTL8153_RMS);
+       ocp_data = tp->netdev->mtu + VLAN_ETH_HLEN + CRC_SIZE;
+       ocp_write_word(tp, MCU_TYPE_PLA, PLA_RMS, ocp_data);
        ocp_write_byte(tp, MCU_TYPE_PLA, PLA_MTPS, MTPS_JUMBO);
 
        ocp_data = ocp_read_word(tp, MCU_TYPE_PLA, PLA_TCR0);
@@ -2950,7 +2951,8 @@ static void r8153_enter_oob(struct r8152 *tp)
                usleep_range(1000, 2000);
        }
 
-       ocp_write_word(tp, MCU_TYPE_PLA, PLA_RMS, RTL8153_RMS);
+       ocp_data = tp->netdev->mtu + VLAN_ETH_HLEN + CRC_SIZE;
+       ocp_write_word(tp, MCU_TYPE_PLA, PLA_RMS, ocp_data);
 
        ocp_data = ocp_read_word(tp, MCU_TYPE_PLA, PLA_TEREDO_CFG);
        ocp_data &= ~TEREDO_WAKE_MASK;
@@ -4200,8 +4202,14 @@ static int rtl8152_change_mtu(struct net_device *dev, 
int new_mtu)
 
        dev->mtu = new_mtu;
 
-       if (netif_running(dev) && netif_carrier_ok(dev))
-               r8153_set_rx_early_size(tp);
+       if (netif_running(dev)) {
+               u32 rms = new_mtu + VLAN_ETH_HLEN + CRC_SIZE;
+
+               ocp_write_word(tp, MCU_TYPE_PLA, PLA_RMS, rms);
+
+               if (netif_carrier_ok(dev))
+                       r8153_set_rx_early_size(tp);
+       }
 
        mutex_unlock(&tp->control);
 
-- 
2.7.4