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Commit ef021194 authored by Jesse Brandeburg's avatar Jesse Brandeburg Committed by David S. Miller
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ixgbe: fix bug when EITR=0 causing no writebacks 



writebacks can be held indefinitely by hardware if EITR=0, when
combined with TXDCTL.WTHRESH=8.  When EITR=0, WTHRESH should be
set back to zero.

Signed-off-by: default avatarJesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f8d1dcaf

drivers/net/ixgbe/ixgbe_ethtool.c

+19 −12
Original line number Original line Diff line number Diff line
@@ -2083,7 +2083,7 @@ static int ixgbe_get_coalesce(struct net_device *netdev, 
 * this function must be called before setting the new value of

 * this function must be called before setting the new value of

 * rx_itr_setting

 * rx_itr_setting

 */

 */

static void ixgbe_reenable_rsc(struct ixgbe_adapter *adapter,

static bool ixgbe_reenable_rsc(struct ixgbe_adapter *adapter,

                               struct ethtool_coalesce *ec)

                               struct ethtool_coalesce *ec)

{

{

	/* check the old value and enable RSC if necessary */

	/* check the old value and enable RSC if necessary */
@@ -2093,11 +2093,9 @@ static void ixgbe_reenable_rsc(struct ixgbe_adapter *adapter, 
		adapter->netdev->features |= NETIF_F_LRO;

		adapter->netdev->features |= NETIF_F_LRO;

		DPRINTK(PROBE, INFO, "rx-usecs set to %d, re-enabling RSC\n",

		DPRINTK(PROBE, INFO, "rx-usecs set to %d, re-enabling RSC\n",

		        ec->rx_coalesce_usecs);

		        ec->rx_coalesce_usecs);

		if (netif_running(adapter->netdev))

		return true;

			ixgbe_reinit_locked(adapter);

		else

			ixgbe_reset(adapter);

	}

	}

	return false;

}

}





static int ixgbe_set_coalesce(struct net_device *netdev,

static int ixgbe_set_coalesce(struct net_device *netdev,
@@ -2106,6 +2104,7 @@ static int ixgbe_set_coalesce(struct net_device *netdev, 
	struct ixgbe_adapter *adapter = netdev_priv(netdev);

	struct ixgbe_adapter *adapter = netdev_priv(netdev);

	struct ixgbe_q_vector *q_vector;

	struct ixgbe_q_vector *q_vector;

	int i;

	int i;

	bool need_reset = false;





	/* don't accept tx specific changes if we've got mixed RxTx vectors */

	/* don't accept tx specific changes if we've got mixed RxTx vectors */

	if (adapter->q_vector[0]->txr_count && adapter->q_vector[0]->rxr_count

	if (adapter->q_vector[0]->txr_count && adapter->q_vector[0]->rxr_count
@@ -2128,7 +2127,7 @@ static int ixgbe_set_coalesce(struct net_device *netdev, 
			return -EINVAL;

			return -EINVAL;





		/* check the old value and enable RSC if necessary */

		/* check the old value and enable RSC if necessary */

		ixgbe_reenable_rsc(adapter, ec);

		need_reset = ixgbe_reenable_rsc(adapter, ec);





		/* store the value in ints/second */

		/* store the value in ints/second */

		adapter->rx_eitr_param = 1000000/ec->rx_coalesce_usecs;

		adapter->rx_eitr_param = 1000000/ec->rx_coalesce_usecs;
@@ -2139,7 +2138,7 @@ static int ixgbe_set_coalesce(struct net_device *netdev, 
		adapter->rx_itr_setting &= ~1;

		adapter->rx_itr_setting &= ~1;

	} else if (ec->rx_coalesce_usecs == 1) {

	} else if (ec->rx_coalesce_usecs == 1) {

		/* check the old value and enable RSC if necessary */

		/* check the old value and enable RSC if necessary */

		ixgbe_reenable_rsc(adapter, ec);

		need_reset = ixgbe_reenable_rsc(adapter, ec);





		/* 1 means dynamic mode */

		/* 1 means dynamic mode */

		adapter->rx_eitr_param = 20000;

		adapter->rx_eitr_param = 20000;
@@ -2164,11 +2163,7 @@ static int ixgbe_set_coalesce(struct net_device *netdev, 
			DPRINTK(PROBE, INFO,

			DPRINTK(PROBE, INFO,

			        "rx-usecs set to 0, disabling RSC\n");

			        "rx-usecs set to 0, disabling RSC\n");





			if (netif_running(netdev))

			need_reset = true;

				ixgbe_reinit_locked(adapter);

			else

				ixgbe_reset(adapter);

			return 0;

		}

		}

	}

	}
@@ -2220,6 +2215,18 @@ static int ixgbe_set_coalesce(struct net_device *netdev, 
		ixgbe_write_eitr(q_vector);

		ixgbe_write_eitr(q_vector);

	}

	}





	/*

	 * do reset here at the end to make sure EITR==0 case is handled

	 * correctly w.r.t stopping tx, and changing TXDCTL.WTHRESH settings

	 * also locks in RSC enable/disable which requires reset

	 */

	if (need_reset) {

		if (netif_running(netdev))

			ixgbe_reinit_locked(adapter);

		else

			ixgbe_reset(adapter);

	}



	return 0;

	return 0;

}

}

drivers/net/ixgbe/ixgbe_main.c

+7 −2
Original line number Original line Diff line number Diff line
@@ -2945,8 +2945,13 @@ static int ixgbe_up_complete(struct ixgbe_adapter *adapter) 
	for (i = 0; i < adapter->num_tx_queues; i++) {

	for (i = 0; i < adapter->num_tx_queues; i++) {

		j = adapter->tx_ring[i]->reg_idx;

		j = adapter->tx_ring[i]->reg_idx;

		txdctl = IXGBE_READ_REG(hw, IXGBE_TXDCTL(j));

		txdctl = IXGBE_READ_REG(hw, IXGBE_TXDCTL(j));

		if (adapter->rx_itr_setting == 0) {

			/* cannot set wthresh when itr==0 */

			txdctl &= ~0x007F0000;

		} else {

			/* enable WTHRESH=8 descriptors, to encourage burst writeback */

			/* enable WTHRESH=8 descriptors, to encourage burst writeback */

			txdctl |= (8 << 16);

			txdctl |= (8 << 16);

		}

		IXGBE_WRITE_REG(hw, IXGBE_TXDCTL(j), txdctl);

		IXGBE_WRITE_REG(hw, IXGBE_TXDCTL(j), txdctl);

	}

	}