2 files changed, 10 insertions, 6 deletions

diff --git a/drivers/net/e1000e/defines.h b/drivers/net/e1000e/defines.h
index 243aa499fe90..9acfecddb273 100644
--- a/drivers/net/e1000e/defines.h
+++ b/drivers/net/e1000e/defines.h
@@ -469,6 +469,8 @@
 #define AUTO_READ_DONE_TIMEOUT      10
 
 /* Flow Control */
+#define E1000_FCRTH_RTH  0x0000FFF8     /* Mask Bits[15:3] for RTH */
+#define E1000_FCRTL_RTL  0x0000FFF8     /* Mask Bits[15:3] for RTL */
 #define E1000_FCRTL_XONE 0x80000000     /* Enable XON frame transmission */
 
 /* Transmit Configuration Word */
diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index 7e412d1168ed..b7a46c513783 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -2751,23 +2751,25 @@ void e1000e_reset(struct e1000_adapter *adapter)
         /*
          * flow control settings
          *
-         * The high water mark must be low enough to fit one full frame
+         * The high water mark must be low enough to fit two full frame
          * (or the size used for early receive) above it in the Rx FIFO.
          * Set it to the lower of:
          * - 90% of the Rx FIFO size, and
          * - the full Rx FIFO size minus the early receive size (for parts
          *   with ERT support assuming ERT set to E1000_ERT_2048), or
-         * - the full Rx FIFO size minus one full frame
+         * - the full Rx FIFO size minus two full frames
          */
-        if (adapter->flags & FLAG_HAS_ERT)
+        if ((adapter->flags & FLAG_HAS_ERT) &&
+            (adapter->netdev->mtu > ETH_DATA_LEN))
                 hwm = min(((pba << 10) * 9 / 10),
                           ((pba << 10) - (E1000_ERT_2048 << 3)));
         else
                 hwm = min(((pba << 10) * 9 / 10),
-                          ((pba << 10) - adapter->max_frame_size));
+                          ((pba << 10) - (2 * adapter->max_frame_size)));
 
-        fc->high_water = hwm & 0xFFF8; /* 8-byte granularity */
-        fc->low_water = fc->high_water - 8;
+        fc->high_water = hwm & E1000_FCRTH_RTH; /* 8-byte granularity */
+        fc->low_water = (fc->high_water - (2 * adapter->max_frame_size));
+        fc->low_water &= E1000_FCRTL_RTL; /* 8-byte granularity */
 
         if (adapter->flags & FLAG_DISABLE_FC_PAUSE_TIME)
                 fc->pause_time = 0xFFFF;