jme: Fix FIFO flush issue

Set the RX FIFO flush watermark lower.
According to Federico and JMicron's reply,
setting it to 16QW would be stable on most platforms.
Otherwise, user might experience packet drop issue.

CC: stable@kernel.org
Reported-by: Federico Quagliata <federico@quagliata.org>
Fixed-by: Federico Quagliata <federico@quagliata.org>
Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 2 insertions, 10 deletions

diff --git a/drivers/net/ethernet/jme.c b/drivers/net/ethernet/jme.c
index 27d651a80f3f..55cbf65512c3 100644
--- a/drivers/net/ethernet/jme.c
+++ b/drivers/net/ethernet/jme.c
@@ -2328,19 +2328,11 @@ jme_change_mtu(struct net_device *netdev, int new_mtu)
                 ((new_mtu) < IPV6_MIN_MTU))
                 return -EINVAL;
 
-        if (new_mtu > 4000) {
-                jme->reg_rxcs &= ~RXCS_FIFOTHNP;
-                jme->reg_rxcs |= RXCS_FIFOTHNP_64QW;
-                jme_restart_rx_engine(jme);
-        } else {
-                jme->reg_rxcs &= ~RXCS_FIFOTHNP;
-                jme->reg_rxcs |= RXCS_FIFOTHNP_128QW;
-                jme_restart_rx_engine(jme);
-        }
 
         netdev->mtu = new_mtu;
         netdev_update_features(netdev);
 
+        jme_restart_rx_engine(jme);
         jme_reset_link(jme);
 
         return 0;
diff --git a/drivers/net/ethernet/jme.h b/drivers/net/ethernet/jme.h
index 4304072bd3c5..3efc897c9913 100644
--- a/drivers/net/ethernet/jme.h
+++ b/drivers/net/ethernet/jme.h
@@ -730,7 +730,7 @@ enum jme_rxcs_values {
         RXCS_RETRYCNT_60        = 0x00000F00,
 
         RXCS_DEFAULT            = RXCS_FIFOTHTP_128T |
-                                  RXCS_FIFOTHNP_128QW |
+                                  RXCS_FIFOTHNP_16QW |
                                   RXCS_DMAREQSZ_128B |
                                   RXCS_RETRYGAP_256ns |
                                   RXCS_RETRYCNT_32,