[PATCH 3.12 077/104] ixgbe: fix rx-usecs range checks for BQL

[Jiri Slaby]

From: Emil Tantilov <emil.s.tantilov@xxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 2e0103810c6fed6a736c4a3af87b0f5c6bd8cd5b upstream.

This patch resolves an issue where the logic used to detect changes in rx-usecs
was incorrect and was masked by the call to ixgbe_update_rsc().

Setting rx-usecs between 0,2-9 and 1,10 and up requires a reset to allow
ixgbe_configure_tx_ring() to set the correct value for TXDCTL.WTHRESH in
order to avoid Tx hangs with BQL enabled.

Signed-off-by: Emil Tantilov <emil.s.tantilov@xxxxxxxxx>
Tested-by: Phil Schmitt <phillip.j.schmitt@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
index e8649abf97c0..2cd86d30508b 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
@@ -2212,13 +2212,13 @@ static int ixgbe_set_coalesce(struct net_device *netdev,
 
 #if IS_ENABLED(CONFIG_BQL)
 	/* detect ITR changes that require update of TXDCTL.WTHRESH */
-	if ((adapter->tx_itr_setting > 1) &&
+	if ((adapter->tx_itr_setting != 1) &&
 	    (adapter->tx_itr_setting < IXGBE_100K_ITR)) {
 		if ((tx_itr_prev == 1) ||
-		    (tx_itr_prev > IXGBE_100K_ITR))
+		    (tx_itr_prev >= IXGBE_100K_ITR))
 			need_reset = true;
 	} else {
-		if ((tx_itr_prev > 1) &&
+		if ((tx_itr_prev != 1) &&
 		    (tx_itr_prev < IXGBE_100K_ITR))
 			need_reset = true;
 	}
-- 
2.0.4

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