ixgbe: Clean up priority based flow control

This change cleans up the logic in the priority based flow control
configuration routines.  Both the 82599 and 82598 based routines perform
similar functions however they are both arranged completely differently.
This patch goes over both of them to clean up the code.

In addition I am dropping the ixgbe_fc_pfc flow control mode and instead
just replacing it with checks for if priority flow control is enabled.
This allows us to maintain some of the link flow control information which
allows for an easier transition between link and priority flow control.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_82598.c

@@ -191,53 +191,46 @@ s32 ixgbe_dcb_config_tx_data_arbiter_82598(struct ixgbe_hw *hw,
  */
 s32 ixgbe_dcb_config_pfc_82598(struct ixgbe_hw *hw, u8 pfc_en)
 {
-	u32 reg;
+	u32 fcrtl, reg;
 	u8  i;
 
-	if (pfc_en) {
-		/* Enable Transmit Priority Flow Control */
-		reg = IXGBE_READ_REG(hw, IXGBE_RMCS);
-		reg &= ~IXGBE_RMCS_TFCE_802_3X;
-		/* correct the reporting of our flow control status */
-		reg |= IXGBE_RMCS_TFCE_PRIORITY;
-		IXGBE_WRITE_REG(hw, IXGBE_RMCS, reg);
-
-		/* Enable Receive Priority Flow Control */
-		reg = IXGBE_READ_REG(hw, IXGBE_FCTRL);
-		reg &= ~IXGBE_FCTRL_RFCE;
-		reg |= IXGBE_FCTRL_RPFCE;
-		IXGBE_WRITE_REG(hw, IXGBE_FCTRL, reg);
-
-		/* Configure pause time */
-		for (i = 0; i < (MAX_TRAFFIC_CLASS >> 1); i++)
-			IXGBE_WRITE_REG(hw, IXGBE_FCTTV(i), 0x68006800);
+	/* Enable Transmit Priority Flow Control */
+	reg = IXGBE_READ_REG(hw, IXGBE_RMCS);
+	reg &= ~IXGBE_RMCS_TFCE_802_3X;
+	reg |= IXGBE_RMCS_TFCE_PRIORITY;
+	IXGBE_WRITE_REG(hw, IXGBE_RMCS, reg);
 
-		/* Configure flow control refresh threshold value */
-		IXGBE_WRITE_REG(hw, IXGBE_FCRTV, 0x3400);
-	}
+	/* Enable Receive Priority Flow Control */
+	reg = IXGBE_READ_REG(hw, IXGBE_FCTRL);
+	reg &= ~(IXGBE_FCTRL_RPFCE | IXGBE_FCTRL_RFCE);
 
-	/*
-	 * Configure flow control thresholds and enable priority flow control
-	 * for each traffic class.
-	 */
-	for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
-		int enabled = pfc_en & (1 << i);
+	if (pfc_en)
+		reg |= IXGBE_FCTRL_RPFCE;
 
-		reg = hw->fc.low_water << 10;
+	IXGBE_WRITE_REG(hw, IXGBE_FCTRL, reg);
 
-		if (enabled == pfc_enabled_tx ||
-		    enabled == pfc_enabled_full)
-			reg |= IXGBE_FCRTL_XONE;
+	fcrtl = (hw->fc.low_water << 10) | IXGBE_FCRTL_XONE;
+	/* Configure PFC Tx thresholds per TC */
+	for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
+		if (!(pfc_en & (1 << i))) {
+			IXGBE_WRITE_REG(hw, IXGBE_FCRTL(i), 0);
+			IXGBE_WRITE_REG(hw, IXGBE_FCRTH(i), 0);
+			continue;
+		}
+
+		reg = (hw->fc.high_water[i] << 10) | IXGBE_FCRTH_FCEN;
+		IXGBE_WRITE_REG(hw, IXGBE_FCRTL(i), fcrtl);
+		IXGBE_WRITE_REG(hw, IXGBE_FCRTH(i), reg);
+	}
 
-		IXGBE_WRITE_REG(hw, IXGBE_FCRTL(i), reg);
+	/* Configure pause time */
+	reg = hw->fc.pause_time * 0x00010001;
+	for (i = 0; i < (MAX_TRAFFIC_CLASS / 2); i++)
+		IXGBE_WRITE_REG(hw, IXGBE_FCTTV(i), reg);
 
-		reg = hw->fc.high_water[i] << 10;
-		if (enabled == pfc_enabled_tx ||
-		    enabled == pfc_enabled_full)
-			reg |= IXGBE_FCRTH_FCEN;
+	/* Configure flow control refresh threshold value */
+	IXGBE_WRITE_REG(hw, IXGBE_FCRTV, hw->fc.pause_time / 2);
 
-		IXGBE_WRITE_REG(hw, IXGBE_FCRTH(i), reg);
-	}
 
 	return 0;
 }

drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_82599.c

@@ -211,24 +211,42 @@ s32 ixgbe_dcb_config_tx_data_arbiter_82599(struct ixgbe_hw *hw,
  */
 s32 ixgbe_dcb_config_pfc_82599(struct ixgbe_hw *hw, u8 pfc_en, u8 *prio_tc)
 {
-	u32 i, j, reg;
+	u32 i, j, fcrtl, reg;
 	u8 max_tc = 0;
 
-	for (i = 0; i < MAX_USER_PRIORITY; i++)
+	/* Enable Transmit Priority Flow Control */
+	IXGBE_WRITE_REG(hw, IXGBE_FCCFG, IXGBE_FCCFG_TFCE_PRIORITY);
+
+	/* Enable Receive Priority Flow Control */
+	reg = IXGBE_READ_REG(hw, IXGBE_MFLCN);
+	reg |= IXGBE_MFLCN_DPF;
+
+	/*
+	 * X540 supports per TC Rx priority flow control.  So
+	 * clear all TCs and only enable those that should be
+	 * enabled.
+	 */
+	reg &= ~(IXGBE_MFLCN_RPFCE_MASK | IXGBE_MFLCN_RFCE);
+
+	if (hw->mac.type == ixgbe_mac_X540)
+		reg |= pfc_en << IXGBE_MFLCN_RPFCE_SHIFT;
+
+	if (pfc_en)
+		reg |= IXGBE_MFLCN_RPFCE;
+
+	IXGBE_WRITE_REG(hw, IXGBE_MFLCN, reg);
+
+	for (i = 0; i < MAX_USER_PRIORITY; i++) {
 		if (prio_tc[i] > max_tc)
 			max_tc = prio_tc[i];
+	}
+
+	fcrtl = (hw->fc.low_water << 10) | IXGBE_FCRTL_XONE;
 
 	/* Configure PFC Tx thresholds per TC */
-	for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
+	for (i = 0; i <= max_tc; i++) {
 		int enabled = 0;
 
-		if (i > max_tc) {
-			reg = 0;
-			IXGBE_WRITE_REG(hw, IXGBE_FCRTL_82599(i), reg);
-			IXGBE_WRITE_REG(hw, IXGBE_FCRTH_82599(i), reg);
-			continue;
-		}
-
 		for (j = 0; j < MAX_USER_PRIORITY; j++) {
 			if ((prio_tc[j] == i) && (pfc_en & (1 << j))) {
 				enabled = 1;
@@ -236,50 +254,29 @@ s32 ixgbe_dcb_config_pfc_82599(struct ixgbe_hw *hw, u8 pfc_en, u8 *prio_tc)
 			}
 		}
 
-		reg = hw->fc.low_water << 10;
-
-		if (enabled)
-			reg |= IXGBE_FCRTL_XONE;
-		IXGBE_WRITE_REG(hw, IXGBE_FCRTL_82599(i), reg);
+		if (enabled) {
+			reg = (hw->fc.high_water[i] << 10) | IXGBE_FCRTH_FCEN;
+			IXGBE_WRITE_REG(hw, IXGBE_FCRTL_82599(i), fcrtl);
+		} else {
+			reg = IXGBE_READ_REG(hw, IXGBE_RXPBSIZE(i)) - 32;
+			IXGBE_WRITE_REG(hw, IXGBE_FCRTL_82599(i), 0);
+		}
 
-		reg = hw->fc.high_water[i] << 10;
-		if (enabled)
-			reg |= IXGBE_FCRTH_FCEN;
 		IXGBE_WRITE_REG(hw, IXGBE_FCRTH_82599(i), reg);
 	}
 
-	if (pfc_en) {
-		/* Configure pause time (2 TCs per register) */
-		reg = hw->fc.pause_time | (hw->fc.pause_time << 16);
-		for (i = 0; i < (MAX_TRAFFIC_CLASS / 2); i++)
-			IXGBE_WRITE_REG(hw, IXGBE_FCTTV(i), reg);
-
-		/* Configure flow control refresh threshold value */
-		IXGBE_WRITE_REG(hw, IXGBE_FCRTV, hw->fc.pause_time / 2);
-
-
-		reg = IXGBE_FCCFG_TFCE_PRIORITY;
-		IXGBE_WRITE_REG(hw, IXGBE_FCCFG, reg);
-		/*
-		 * Enable Receive PFC
-		 * 82599 will always honor XOFF frames we receive when
-		 * we are in PFC mode however X540 only honors enabled
-		 * traffic classes.
-		 */
-		reg = IXGBE_READ_REG(hw, IXGBE_MFLCN);
-		reg &= ~IXGBE_MFLCN_RFCE;
-		reg |= IXGBE_MFLCN_RPFCE | IXGBE_MFLCN_DPF;
-
-		if (hw->mac.type == ixgbe_mac_X540) {
-			reg &= ~IXGBE_MFLCN_RPFCE_MASK;
-			reg |= pfc_en << IXGBE_MFLCN_RPFCE_SHIFT;
-		}
+	for (; i < MAX_TRAFFIC_CLASS; i++) {
+		IXGBE_WRITE_REG(hw, IXGBE_FCRTL_82599(i), 0);
+		IXGBE_WRITE_REG(hw, IXGBE_FCRTH_82599(i), 0);
+	}
 
-		IXGBE_WRITE_REG(hw, IXGBE_MFLCN, reg);
+	/* Configure pause time (2 TCs per register) */
+	reg = hw->fc.pause_time * 0x00010001;
+	for (i = 0; i < (MAX_TRAFFIC_CLASS / 2); i++)
+		IXGBE_WRITE_REG(hw, IXGBE_FCTTV(i), reg);
 
-	} else {
-		hw->mac.ops.fc_enable(hw);
-	}
+	/* Configure flow control refresh threshold value */
+	IXGBE_WRITE_REG(hw, IXGBE_FCRTV, hw->fc.pause_time / 2);
 
 	return 0;
 }

drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c

@@ -338,6 +338,8 @@ static void ixgbe_dcbnl_devreset(struct net_device *dev)
 static u8 ixgbe_dcbnl_set_all(struct net_device *netdev)
 {
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
+	struct ixgbe_dcb_config *dcb_cfg = &adapter->dcb_cfg;
+	struct ixgbe_hw *hw = &adapter->hw;
 	int ret = DCB_NO_HW_CHG;
 	int i;
 
@@ -350,32 +352,6 @@ static u8 ixgbe_dcbnl_set_all(struct net_device *netdev)
 	if (!adapter->dcb_set_bitmap)
 		return ret;
 
-	if (adapter->dcb_cfg.pfc_mode_enable) {
-		switch (adapter->hw.mac.type) {
-		case ixgbe_mac_82599EB:
-		case ixgbe_mac_X540:
-			if (adapter->hw.fc.current_mode != ixgbe_fc_pfc)
-				adapter->last_lfc_mode =
-				                  adapter->hw.fc.current_mode;
-			break;
-		default:
-			break;
-		}
-		adapter->hw.fc.requested_mode = ixgbe_fc_pfc;
-	} else {
-		switch (adapter->hw.mac.type) {
-		case ixgbe_mac_82598EB:
-			adapter->hw.fc.requested_mode = ixgbe_fc_none;
-			break;
-		case ixgbe_mac_82599EB:
-		case ixgbe_mac_X540:
-			adapter->hw.fc.requested_mode = adapter->last_lfc_mode;
-			break;
-		default:
-			break;
-		}
-	}
-
 	if (adapter->dcb_set_bitmap & (BIT_PG_TX|BIT_PG_RX)) {
 		u16 refill[MAX_TRAFFIC_CLASS], max[MAX_TRAFFIC_CLASS];
 		u8 bwg_id[MAX_TRAFFIC_CLASS], prio_type[MAX_TRAFFIC_CLASS];
@@ -388,23 +364,19 @@ static u8 ixgbe_dcbnl_set_all(struct net_device *netdev)
 			max_frame = max(max_frame, IXGBE_FCOE_JUMBO_FRAME_SIZE);
 #endif
 
-		ixgbe_dcb_calculate_tc_credits(&adapter->hw, &adapter->dcb_cfg,
-					       max_frame, DCB_TX_CONFIG);
-		ixgbe_dcb_calculate_tc_credits(&adapter->hw, &adapter->dcb_cfg,
-					       max_frame, DCB_RX_CONFIG);
+		ixgbe_dcb_calculate_tc_credits(hw, dcb_cfg, max_frame,
+					       DCB_TX_CONFIG);
+		ixgbe_dcb_calculate_tc_credits(hw, dcb_cfg, max_frame,
+					       DCB_RX_CONFIG);
 
-		ixgbe_dcb_unpack_refill(&adapter->dcb_cfg,
-					DCB_TX_CONFIG, refill);
-		ixgbe_dcb_unpack_max(&adapter->dcb_cfg, max);
-		ixgbe_dcb_unpack_bwgid(&adapter->dcb_cfg,
-				       DCB_TX_CONFIG, bwg_id);
-		ixgbe_dcb_unpack_prio(&adapter->dcb_cfg,
-				      DCB_TX_CONFIG, prio_type);
-		ixgbe_dcb_unpack_map(&adapter->dcb_cfg,
-				     DCB_TX_CONFIG, prio_tc);
+		ixgbe_dcb_unpack_refill(dcb_cfg, DCB_TX_CONFIG, refill);
+		ixgbe_dcb_unpack_max(dcb_cfg, max);
+		ixgbe_dcb_unpack_bwgid(dcb_cfg, DCB_TX_CONFIG, bwg_id);
+		ixgbe_dcb_unpack_prio(dcb_cfg, DCB_TX_CONFIG, prio_type);
+		ixgbe_dcb_unpack_map(dcb_cfg, DCB_TX_CONFIG, prio_tc);
 
-		ixgbe_dcb_hw_ets_config(&adapter->hw, refill, max,
-					bwg_id, prio_type, prio_tc);
+		ixgbe_dcb_hw_ets_config(hw, refill, max, bwg_id,
+					prio_type, prio_tc);
 
 		for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++)
 			netdev_set_prio_tc_map(netdev, i, prio_tc[i]);
@@ -413,20 +385,19 @@ static u8 ixgbe_dcbnl_set_all(struct net_device *netdev)
 	}
 
 	if (adapter->dcb_set_bitmap & BIT_PFC) {
-		u8 pfc_en;
-		u8 prio_tc[MAX_USER_PRIORITY];
-
-		ixgbe_dcb_unpack_map(&adapter->dcb_cfg,
-				     DCB_TX_CONFIG, prio_tc);
-		ixgbe_dcb_unpack_pfc(&adapter->dcb_cfg, &pfc_en);
-		ixgbe_dcb_hw_pfc_config(&adapter->hw, pfc_en, prio_tc);
-		if (ret != DCB_HW_CHG_RST)
-			ret = DCB_HW_CHG;
+		if (dcb_cfg->pfc_mode_enable) {
+			u8 pfc_en;
+			u8 prio_tc[MAX_USER_PRIORITY];
+
+			ixgbe_dcb_unpack_map(dcb_cfg, DCB_TX_CONFIG, prio_tc);
+			ixgbe_dcb_unpack_pfc(dcb_cfg, &pfc_en);
+			ixgbe_dcb_hw_pfc_config(hw, pfc_en, prio_tc);
+		} else {
+			hw->mac.ops.fc_enable(hw);
+		}
+		ret = DCB_HW_CHG;
 	}
 
-	if (adapter->dcb_cfg.pfc_mode_enable)
-		adapter->hw.fc.current_mode = ixgbe_fc_pfc;
-
 #ifdef IXGBE_FCOE
 	/* Reprogam FCoE hardware offloads when the traffic class
 	 * FCoE is using changes. This happens if the APP info
@@ -647,7 +618,9 @@ static int ixgbe_dcbnl_ieee_setpfc(struct net_device *dev,
 				   struct ieee_pfc *pfc)
 {
 	struct ixgbe_adapter *adapter = netdev_priv(dev);
+	struct ixgbe_hw *hw = &adapter->hw;
 	u8 *prio_tc;
+	int err;
 
 	if (!(adapter->dcbx_cap & DCB_CAP_DCBX_VER_IEEE))
 		return -EINVAL;
@@ -659,16 +632,16 @@ static int ixgbe_dcbnl_ieee_setpfc(struct net_device *dev,
 			return -ENOMEM;
 	}
 
-	if (pfc->pfc_en) {
-		adapter->last_lfc_mode = adapter->hw.fc.current_mode;
-		adapter->hw.fc.current_mode = ixgbe_fc_pfc;
-	} else {
-		adapter->hw.fc.current_mode = adapter->last_lfc_mode;
-	}
-
 	prio_tc = adapter->ixgbe_ieee_ets->prio_tc;
 	memcpy(adapter->ixgbe_ieee_pfc, pfc, sizeof(*adapter->ixgbe_ieee_pfc));
-	return ixgbe_dcb_hw_pfc_config(&adapter->hw, pfc->pfc_en, prio_tc);
+
+	/* Enable link flow control parameters if PFC is disabled */
+	if (pfc->pfc_en)
+		err = ixgbe_dcb_hw_pfc_config(hw, pfc->pfc_en, prio_tc);
+	else
+		err = hw->mac.ops.fc_enable(hw);
+
+	return err;
 }
 
 static int ixgbe_dcbnl_ieee_setapp(struct net_device *dev,

drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c

@@ -391,11 +391,6 @@ static void ixgbe_get_pauseparam(struct net_device *netdev,
 	} else if (hw->fc.current_mode == ixgbe_fc_full) {
 		pause->rx_pause = 1;
 		pause->tx_pause = 1;
-#ifdef CONFIG_DCB
-	} else if (hw->fc.current_mode == ixgbe_fc_pfc) {
-		pause->rx_pause = 0;
-		pause->tx_pause = 0;
-#endif
 	}
 }
 
@@ -404,21 +399,14 @@ static int ixgbe_set_pauseparam(struct net_device *netdev,
 {
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
 	struct ixgbe_hw *hw = &adapter->hw;
-	struct ixgbe_fc_info fc;
+	struct ixgbe_fc_info fc = hw->fc;
 
-#ifdef CONFIG_DCB
-	if (adapter->dcb_cfg.pfc_mode_enable ||
-		((hw->mac.type == ixgbe_mac_82598EB) &&
-		(adapter->flags & IXGBE_FLAG_DCB_ENABLED)))
+	/* 82598 does no support link flow control with DCB enabled */
+	if ((hw->mac.type == ixgbe_mac_82598EB) &&
+	    (adapter->flags & IXGBE_FLAG_DCB_ENABLED))
 		return -EINVAL;
 
-#endif
-	fc = hw->fc;
-
-	if (pause->autoneg != AUTONEG_ENABLE)
-		fc.disable_fc_autoneg = true;
-	else
-		fc.disable_fc_autoneg = false;
+	fc.disable_fc_autoneg = (pause->autoneg != AUTONEG_ENABLE);
 
 	if ((pause->rx_pause && pause->tx_pause) || pause->autoneg)
 		fc.requested_mode = ixgbe_fc_full;
@@ -426,14 +414,8 @@ static int ixgbe_set_pauseparam(struct net_device *netdev,
 		fc.requested_mode = ixgbe_fc_rx_pause;
 	else if (!pause->rx_pause && pause->tx_pause)
 		fc.requested_mode = ixgbe_fc_tx_pause;
-	else if (!pause->rx_pause && !pause->tx_pause)
-		fc.requested_mode = ixgbe_fc_none;
 	else
-		return -EINVAL;
-
-#ifdef CONFIG_DCB
-	adapter->last_lfc_mode = fc.requested_mode;
-#endif
+		fc.requested_mode = ixgbe_fc_none;
 
 	/* if the thing changed then we'll update and use new autoneg */
 	if (memcmp(&fc, &hw->fc, sizeof(struct ixgbe_fc_info))) {

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -610,39 +610,50 @@ void ixgbe_unmap_and_free_tx_resource(struct ixgbe_ring *ring,
 	/* tx_buffer must be completely set up in the transmit path */
 }
 
-static void ixgbe_update_xoff_received(struct ixgbe_adapter *adapter)
+static void ixgbe_update_xoff_rx_lfc(struct ixgbe_adapter *adapter)
 {
 	struct ixgbe_hw *hw = &adapter->hw;
 	struct ixgbe_hw_stats *hwstats = &adapter->stats;
-	u32 data = 0;
-	u32 xoff[8] = {0};
 	int i;
+	u32 data;
 
-	if ((hw->fc.current_mode == ixgbe_fc_full) ||
-	    (hw->fc.current_mode == ixgbe_fc_rx_pause)) {
-		switch (hw->mac.type) {
-		case ixgbe_mac_82598EB:
-			data = IXGBE_READ_REG(hw, IXGBE_LXOFFRXC);
-			break;
-		default:
-			data = IXGBE_READ_REG(hw, IXGBE_LXOFFRXCNT);
-		}
-		hwstats->lxoffrxc += data;
+	if ((hw->fc.current_mode != ixgbe_fc_full) &&
+	    (hw->fc.current_mode != ixgbe_fc_rx_pause))
+		return;
 
-		/* refill credits (no tx hang) if we received xoff */
-		if (!data)
-			return;
+	switch (hw->mac.type) {
+	case ixgbe_mac_82598EB:
+		data = IXGBE_READ_REG(hw, IXGBE_LXOFFRXC);
+		break;
+	default:
+		data = IXGBE_READ_REG(hw, IXGBE_LXOFFRXCNT);
+	}
+	hwstats->lxoffrxc += data;
 
-		for (i = 0; i < adapter->num_tx_queues; i++)
-			clear_bit(__IXGBE_HANG_CHECK_ARMED,
-				  &adapter->tx_ring[i]->state);
+	/* refill credits (no tx hang) if we received xoff */
+	if (!data)
 		return;
-	} else if (((adapter->dcbx_cap & DCB_CAP_DCBX_VER_CEE) &&
-		    !(adapter->dcb_cfg.pfc_mode_enable)) ||
-		   ((adapter->dcbx_cap & DCB_CAP_DCBX_VER_IEEE) &&
-		    adapter->ixgbe_ieee_pfc &&
-		    !(adapter->ixgbe_ieee_pfc->pfc_en)))
+
+	for (i = 0; i < adapter->num_tx_queues; i++)
+		clear_bit(__IXGBE_HANG_CHECK_ARMED,
+			  &adapter->tx_ring[i]->state);
+}
+
+static void ixgbe_update_xoff_received(struct ixgbe_adapter *adapter)
+{
+	struct ixgbe_hw *hw = &adapter->hw;
+	struct ixgbe_hw_stats *hwstats = &adapter->stats;
+	u32 xoff[8] = {0};
+	int i;
+	bool pfc_en = adapter->dcb_cfg.pfc_mode_enable;
+
+	if (adapter->ixgbe_ieee_pfc)
+		pfc_en |= !!(adapter->ixgbe_ieee_pfc->pfc_en);
+
+	if (!(adapter->flags & IXGBE_FLAG_DCB_ENABLED) || !pfc_en) {
+		ixgbe_update_xoff_rx_lfc(adapter);
 		return;
+	}
 
 	/* update stats for each tc, only valid with PFC enabled */
 	for (i = 0; i < MAX_TX_PACKET_BUFFERS; i++) {
@@ -4403,9 +4414,6 @@ static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter)
 	/* default flow control settings */
 	hw->fc.requested_mode = ixgbe_fc_full;
 	hw->fc.current_mode = ixgbe_fc_full;	/* init for ethtool output */
-#ifdef CONFIG_DCB
-	adapter->last_lfc_mode = hw->fc.current_mode;
-#endif
 	ixgbe_pbthresh_setup(adapter);
 	hw->fc.pause_time = IXGBE_DEFAULT_FCPAUSE;
 	hw->fc.send_xon = true;
@@ -6542,15 +6550,17 @@ int ixgbe_setup_tc(struct net_device *dev, u8 tc)
 
 	if (tc) {
 		netdev_set_num_tc(dev, tc);
-		adapter->last_lfc_mode = adapter->hw.fc.current_mode;
 		adapter->flags |= IXGBE_FLAG_DCB_ENABLED;
 		adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;
 
-		if (adapter->hw.mac.type == ixgbe_mac_82598EB)
+		if (adapter->hw.mac.type == ixgbe_mac_82598EB) {
+			adapter->last_lfc_mode = adapter->hw.fc.requested_mode;
 			adapter->hw.fc.requested_mode = ixgbe_fc_none;
+		}
 	} else {
 		netdev_reset_tc(dev);
-		adapter->hw.fc.requested_mode = adapter->last_lfc_mode;
+		if (adapter->hw.mac.type == ixgbe_mac_82598EB)
+			adapter->hw.fc.requested_mode = adapter->last_lfc_mode;
 
 		adapter->flags &= ~IXGBE_FLAG_DCB_ENABLED;
 		adapter->flags |= IXGBE_FLAG_FDIR_HASH_CAPABLE;

drivers/net/ethernet/intel/ixgbe/ixgbe_type.h

@@ -2573,9 +2573,6 @@ enum ixgbe_fc_mode {
 	ixgbe_fc_rx_pause,
 	ixgbe_fc_tx_pause,
 	ixgbe_fc_full,
-#ifdef CONFIG_DCB
-	ixgbe_fc_pfc,
-#endif
 	ixgbe_fc_default
 };