diff --git a/drivers/net/ixgbe/ixgbe.h b/drivers/net/ixgbe/ixgbe.h
index 0b54717..c26433d 100644
--- a/drivers/net/ixgbe/ixgbe.h
+++ b/drivers/net/ixgbe/ixgbe.h
@@ -189,10 +189,11 @@
 };
 
 /* Helper macros to switch between ints/sec and what the register uses.
- * And yes, it's the same math going both ways.
+ * And yes, it's the same math going both ways.  The lowest value
+ * supported by all of the ixgbe hardware is 8.
  */
 #define EITR_INTS_PER_SEC_TO_REG(_eitr) \
-	((_eitr) ? (1000000000 / ((_eitr) * 256)) : 0)
+	((_eitr) ? (1000000000 / ((_eitr) * 256)) : 8)
 #define EITR_REG_TO_INTS_PER_SEC EITR_INTS_PER_SEC_TO_REG
 
 #define IXGBE_DESC_UNUSED(R) \
@@ -366,5 +367,6 @@
 extern int ixgbe_init_interrupt_scheme(struct ixgbe_adapter *adapter);
 void ixgbe_napi_add_all(struct ixgbe_adapter *adapter);
 void ixgbe_napi_del_all(struct ixgbe_adapter *adapter);
+extern void ixgbe_write_eitr(struct ixgbe_adapter *, int, u32);
 
 #endif /* _IXGBE_H_ */
diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c b/drivers/net/ixgbe/ixgbe_ethtool.c
index ae38bca..3a99781 100644
--- a/drivers/net/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ixgbe/ixgbe_ethtool.c
@@ -977,40 +977,47 @@
                               struct ethtool_coalesce *ec)
 {
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
-	struct ixgbe_hw *hw = &adapter->hw;
 	int i;
 
 	if (ec->tx_max_coalesced_frames_irq)
 		adapter->tx_ring[0].work_limit = ec->tx_max_coalesced_frames_irq;
 
 	if (ec->rx_coalesce_usecs > 1) {
+		/* check the limits */
+		if ((1000000/ec->rx_coalesce_usecs > IXGBE_MAX_INT_RATE) ||
+		    (1000000/ec->rx_coalesce_usecs < IXGBE_MIN_INT_RATE))
+			return -EINVAL;
+
 		/* store the value in ints/second */
 		adapter->eitr_param = 1000000/ec->rx_coalesce_usecs;
 
 		/* static value of interrupt rate */
 		adapter->itr_setting = adapter->eitr_param;
-		/* clear the lower bit */
+		/* clear the lower bit as its used for dynamic state */
 		adapter->itr_setting &= ~1;
 	} else if (ec->rx_coalesce_usecs == 1) {
 		/* 1 means dynamic mode */
 		adapter->eitr_param = 20000;
 		adapter->itr_setting = 1;
 	} else {
-		/* any other value means disable eitr, which is best
-		 * served by setting the interrupt rate very high */
-		adapter->eitr_param = 3000000;
+		/*
+		 * any other value means disable eitr, which is best
+		 * served by setting the interrupt rate very high
+		 */
+		adapter->eitr_param = IXGBE_MAX_INT_RATE;
 		adapter->itr_setting = 0;
 	}
 
 	for (i = 0; i < adapter->num_msix_vectors - NON_Q_VECTORS; i++) {
 		struct ixgbe_q_vector *q_vector = &adapter->q_vector[i];
 		if (q_vector->txr_count && !q_vector->rxr_count)
+			/* tx vector gets half the rate */
 			q_vector->eitr = (adapter->eitr_param >> 1);
 		else
 			/* rx only or mixed */
 			q_vector->eitr = adapter->eitr_param;
-		IXGBE_WRITE_REG(hw, IXGBE_EITR(i),
-		                EITR_INTS_PER_SEC_TO_REG(q_vector->eitr));
+		ixgbe_write_eitr(adapter, i,
+		                 EITR_INTS_PER_SEC_TO_REG(q_vector->eitr));
 	}
 
 	return 0;
diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index 881bbf9..76fd5c6 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -808,10 +808,14 @@
 		/* if this is a tx only vector halve the interrupt rate */
 		if (q_vector->txr_count && !q_vector->rxr_count)
 			q_vector->eitr = (adapter->eitr_param >> 1);
-		else
+		else if (q_vector->rxr_count)
 			/* rx only */
 			q_vector->eitr = adapter->eitr_param;
 
+		/*
+		 * since ths is initial set up don't need to call
+		 * ixgbe_write_eitr helper
+		 */
 		IXGBE_WRITE_REG(&adapter->hw, IXGBE_EITR(v_idx),
 		                EITR_INTS_PER_SEC_TO_REG(q_vector->eitr));
 	}
@@ -896,10 +900,35 @@
 	return retval;
 }
 
+/**
+ * ixgbe_write_eitr - write EITR register in hardware specific way
+ * @adapter: pointer to adapter struct
+ * @v_idx: vector index into q_vector array
+ * @itr_reg: new value to be written in *register* format, not ints/s
+ *
+ * This function is made to be called by ethtool and by the driver
+ * when it needs to update EITR registers at runtime.  Hardware
+ * specific quirks/differences are taken care of here.
+ */
+void ixgbe_write_eitr(struct ixgbe_adapter *adapter, int v_idx, u32 itr_reg)
+{
+	struct ixgbe_hw *hw = &adapter->hw;
+	if (adapter->hw.mac.type == ixgbe_mac_82598EB) {
+		/* must write high and low 16 bits to reset counter */
+		itr_reg |= (itr_reg << 16);
+	} else if (adapter->hw.mac.type == ixgbe_mac_82599EB) {
+		/*
+		 * set the WDIS bit to not clear the timer bits and cause an
+		 * immediate assertion of the interrupt
+		 */
+		itr_reg |= IXGBE_EITR_CNT_WDIS;
+	}
+	IXGBE_WRITE_REG(hw, IXGBE_EITR(v_idx), itr_reg);
+}
+
 static void ixgbe_set_itr_msix(struct ixgbe_q_vector *q_vector)
 {
 	struct ixgbe_adapter *adapter = q_vector->adapter;
-	struct ixgbe_hw *hw = &adapter->hw;
 	u32 new_itr;
 	u8 current_itr, ret_itr;
 	int i, r_idx, v_idx = ((void *)q_vector - (void *)(adapter->q_vector)) /
@@ -954,17 +983,13 @@
 
 	if (new_itr != q_vector->eitr) {
 		u32 itr_reg;
+
+		/* save the algorithm value here, not the smoothed one */
+		q_vector->eitr = new_itr;
 		/* do an exponential smoothing */
 		new_itr = ((q_vector->eitr * 90)/100) + ((new_itr * 10)/100);
-		q_vector->eitr = new_itr;
 		itr_reg = EITR_INTS_PER_SEC_TO_REG(new_itr);
-		if (adapter->hw.mac.type == ixgbe_mac_82599EB)
-			/* Resolution is 2 usec on 82599, so halve the rate */
-			itr_reg >>= 1;
-		/* must write high and low 16 bits to reset counter */
-		DPRINTK(TX_ERR, DEBUG, "writing eitr(%d): %08X\n", v_idx,
-		        itr_reg);
-		IXGBE_WRITE_REG(hw, IXGBE_EITR(v_idx), itr_reg | (itr_reg)<<16);
+		ixgbe_write_eitr(adapter, v_idx, itr_reg);
 	}
 
 	return;
@@ -1141,7 +1166,7 @@
 	/* If all Rx work done, exit the polling mode */
 	if (work_done < budget) {
 		napi_complete(napi);
-		if (adapter->itr_setting & 3)
+		if (adapter->itr_setting & 1)
 			ixgbe_set_itr_msix(q_vector);
 		if (!test_bit(__IXGBE_DOWN, &adapter->state))
 			IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMS, rx_ring->v_idx);
@@ -1190,7 +1215,7 @@
 	/* If all Rx work done, exit the polling mode */
 	if (work_done < budget) {
 		napi_complete(napi);
-		if (adapter->itr_setting & 3)
+		if (adapter->itr_setting & 1)
 			ixgbe_set_itr_msix(q_vector);
 		if (!test_bit(__IXGBE_DOWN, &adapter->state))
 			IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMS, enable_mask);
@@ -1360,7 +1385,6 @@
 
 static void ixgbe_set_itr(struct ixgbe_adapter *adapter)
 {
-	struct ixgbe_hw *hw = &adapter->hw;
 	struct ixgbe_q_vector *q_vector = adapter->q_vector;
 	u8 current_itr;
 	u32 new_itr = q_vector->eitr;
@@ -1395,15 +1419,13 @@
 
 	if (new_itr != q_vector->eitr) {
 		u32 itr_reg;
+
+		/* save the algorithm value here, not the smoothed one */
+		q_vector->eitr = new_itr;
 		/* do an exponential smoothing */
 		new_itr = ((q_vector->eitr * 90)/100) + ((new_itr * 10)/100);
-		q_vector->eitr = new_itr;
 		itr_reg = EITR_INTS_PER_SEC_TO_REG(new_itr);
-		if (adapter->hw.mac.type == ixgbe_mac_82599EB)
-			/* Resolution is 2 usec on 82599, so halve the rate */
-			itr_reg >>= 1;
-		/* must write high and low 16 bits to reset counter */
-		IXGBE_WRITE_REG(hw, IXGBE_EITR(0), itr_reg | (itr_reg)<<16);
+		ixgbe_write_eitr(adapter, 0, itr_reg);
 	}
 
 	return;
@@ -1701,7 +1723,7 @@
 	                  0xA54F2BEC, 0xEA49AF7C, 0xE214AD3D, 0xB855AABE,
 	                  0x6A3E67EA, 0x14364D17, 0x3BED200D};
 	u32 fctrl, hlreg0;
-	u32 reta = 0, mrqc;
+	u32 reta = 0, mrqc = 0;
 	u32 rdrxctl;
 	int rx_buf_len;
 
@@ -2589,7 +2611,7 @@
 	/* If budget not fully consumed, exit the polling mode */
 	if (work_done < budget) {
 		napi_complete(napi);
-		if (adapter->itr_setting & 3)
+		if (adapter->itr_setting & 1)
 			ixgbe_set_itr(adapter);
 		if (!test_bit(__IXGBE_DOWN, &adapter->state))
 			ixgbe_irq_enable(adapter);
diff --git a/drivers/net/ixgbe/ixgbe_type.h b/drivers/net/ixgbe/ixgbe_type.h
index 6090593..95fc36c 100644
--- a/drivers/net/ixgbe/ixgbe_type.h
+++ b/drivers/net/ixgbe/ixgbe_type.h
@@ -98,9 +98,18 @@
 #define IXGBE_EIMS_EX(_i)   (0x00AA0 + (_i) * 4)
 #define IXGBE_EIMC_EX(_i)   (0x00AB0 + (_i) * 4)
 #define IXGBE_EIAM_EX(_i)   (0x00AD0 + (_i) * 4)
+/*
+ * 82598 EITR is 16 bits but set the limits based on the max
+ * supported by all ixgbe hardware.  82599 EITR is only 12 bits,
+ * with the lower 3 always zero.
+ */
+#define IXGBE_MAX_INT_RATE 488281
+#define IXGBE_MIN_INT_RATE 956
+#define IXGBE_MAX_EITR     0x00000FF8
+#define IXGBE_MIN_EITR     8
 #define IXGBE_EITR(_i)  (((_i) <= 23) ? (0x00820 + ((_i) * 4)) : \
                          (0x012300 + (((_i) - 24) * 4)))
-#define IXGBE_EITR_ITR_INT_MASK 0x00000FFF
+#define IXGBE_EITR_ITR_INT_MASK 0x00000FF8
 #define IXGBE_EITR_LLI_MOD      0x00008000
 #define IXGBE_EITR_CNT_WDIS     0x80000000
 #define IXGBE_IVAR(_i)  (0x00900 + ((_i) * 4)) /* 24 at 0x900-0x960 */