From ef021194d262bdfa706dc5755596e252175a6bbc Mon Sep 17 00:00:00 2001 From: Jesse Brandeburg Date: Tue, 27 Apr 2010 01:37:41 +0000 Subject: [PATCH] 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: Jesse Brandeburg Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- drivers/net/ixgbe/ixgbe_ethtool.c | 31 +++++++++++++++++++------------ drivers/net/ixgbe/ixgbe_main.c | 9 +++++++-- 2 files changed, 26 insertions(+), 14 deletions(-) diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c b/drivers/net/ixgbe/ixgbe_ethtool.c index 1ae0201f5aa..5f8c6ab7a98 100644 --- a/drivers/net/ixgbe/ixgbe_ethtool.c +++ b/drivers/net/ixgbe/ixgbe_ethtool.c @@ -2083,7 +2083,7 @@ static int ixgbe_get_coalesce(struct net_device *netdev, * this function must be called before setting the new value of * 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) { /* 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; DPRINTK(PROBE, INFO, "rx-usecs set to %d, re-enabling RSC\n", ec->rx_coalesce_usecs); - if (netif_running(adapter->netdev)) - ixgbe_reinit_locked(adapter); - else - ixgbe_reset(adapter); + return true; } + return false; } 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_q_vector *q_vector; int i; + bool need_reset = false; /* 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 @@ -2128,7 +2127,7 @@ static int ixgbe_set_coalesce(struct net_device *netdev, return -EINVAL; /* 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 */ 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; } else if (ec->rx_coalesce_usecs == 1) { /* 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 */ adapter->rx_eitr_param = 20000; @@ -2164,11 +2163,7 @@ static int ixgbe_set_coalesce(struct net_device *netdev, DPRINTK(PROBE, INFO, "rx-usecs set to 0, disabling RSC\n"); - if (netif_running(netdev)) - ixgbe_reinit_locked(adapter); - else - ixgbe_reset(adapter); - return 0; + need_reset = true; } } @@ -2220,6 +2215,18 @@ static int ixgbe_set_coalesce(struct net_device *netdev, 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; } diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c index 0c4ca6822b7..fe7e260e015 100644 --- a/drivers/net/ixgbe/ixgbe_main.c +++ b/drivers/net/ixgbe/ixgbe_main.c @@ -2945,8 +2945,13 @@ static int ixgbe_up_complete(struct ixgbe_adapter *adapter) for (i = 0; i < adapter->num_tx_queues; i++) { j = adapter->tx_ring[i]->reg_idx; txdctl = IXGBE_READ_REG(hw, IXGBE_TXDCTL(j)); - /* enable WTHRESH=8 descriptors, to encourage burst writeback */ - txdctl |= (8 << 16); + if (adapter->rx_itr_setting == 0) { + /* cannot set wthresh when itr==0 */ + txdctl &= ~0x007F0000; + } else { + /* enable WTHRESH=8 descriptors, to encourage burst writeback */ + txdctl |= (8 << 16); + } IXGBE_WRITE_REG(hw, IXGBE_TXDCTL(j), txdctl); }