diff mbox series

[v2] net/ixgbe: fix TDH register setting issue

Message ID 20181120055921.8209-1-yanglong.wu@intel.com (mailing list archive)
State Accepted, archived
Delegated to: Qi Zhang
Headers
Series [v2] net/ixgbe: fix TDH register setting issue |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK
ci/mellanox-Performance-Testing success Performance Testing PASS
ci/intel-Performance-Testing success Performance Testing PASS

Commit Message

Yanglong Wu Nov. 20, 2018, 5:59 a.m. UTC 
  The only time that software should write to the TDH register
is after a reset (hardware reset or CTRL.RST) and
before enabling the transmit function (TXDCTL.ENABLE).
If software were to write to this register while the transmit
function was enabled, the on-chip descriptor buffers might
be invalidated and the hardware could become confused.

cc stable@dpdk.org
Signed-off-by: Yanglong Wu <yanglong.wu@intel.com>
---
v2:
change fix commit
---
 drivers/net/ixgbe/ixgbe_rxtx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Qi Zhang Nov. 20, 2018, 7:49 p.m. UTC | #1 
> -----Original Message-----
> From: Wu, Yanglong
> Sent: Monday, November 19, 2018 9:59 PM
> To: dev@dpdk.org
> Cc: Zhang, Qi Z <qi.z.zhang@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>;
> Wu, Yanglong <yanglong.wu@intel.com>
> Subject: [PATCH v2] net/ixgbe: fix TDH register setting issue
> 
> The only time that software should write to the TDH register is after a reset
> (hardware reset or CTRL.RST) and before enabling the transmit function
> (TXDCTL.ENABLE).
> If software were to write to this register while the transmit function was
> enabled, the on-chip descriptor buffers might be invalidated and the hardware
> could become confused.
> 
> cc stable@dpdk.org

Cc: stable@dpdk.org

> Signed-off-by: Yanglong Wu <yanglong.wu@intel.com>

Acked-by: Qi Zhang <qi.z.zhang@intel.com>

Applied to dpdk-next-net-intel with adding below fix line
Fixes: 029fd06d40fa ("ixgbe: queue start and stop")

Thanks
Qi
diff mbox series

Patch

diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
index 2f0262ae1..ddc7efa87 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -5264,6 +5264,7 @@  ixgbe_dev_tx_queue_start(struct rte_eth_dev *dev, uint16_t tx_queue_id)
 	hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 
 	txq = dev->data->tx_queues[tx_queue_id];
+	IXGBE_WRITE_REG(hw, IXGBE_TDH(txq->reg_idx), 0);
 	txdctl = IXGBE_READ_REG(hw, IXGBE_TXDCTL(txq->reg_idx));
 	txdctl |= IXGBE_TXDCTL_ENABLE;
 	IXGBE_WRITE_REG(hw, IXGBE_TXDCTL(txq->reg_idx), txdctl);
@@ -5281,7 +5282,6 @@  ixgbe_dev_tx_queue_start(struct rte_eth_dev *dev, uint16_t tx_queue_id)
 				tx_queue_id);
 	}
 	rte_wmb();
-	IXGBE_WRITE_REG(hw, IXGBE_TDH(txq->reg_idx), 0);
 	IXGBE_WRITE_REG(hw, IXGBE_TDT(txq->reg_idx), 0);
 	dev->data->tx_queue_state[tx_queue_id] = RTE_ETH_QUEUE_STATE_STARTED;