patch 'net/txgbe: fix Tx write-back pointer reset' has been queued to stable release 25.11.3

[Kevin Traynor]

Hi,

FYI, your patch has been queued to stable release 25.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 08/04/26. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/kevintraynor/dpdk-stable

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable/commit/0dfbe9c7e9befa9e54b4e341cf1bf96ea35a0d84

Thanks.

Kevin

---
>From 0dfbe9c7e9befa9e54b4e341cf1bf96ea35a0d84 Mon Sep 17 00:00:00 2001
From: Zaiyu Wang <zaiyuwang at trustnetic.com>
Date: Wed, 24 Jun 2026 19:52:51 +0800
Subject: [PATCH] net/txgbe: fix Tx write-back pointer reset

[ upstream commit a3750e3057e0f22a746da7f92e25f855fb28ab44 ]

The write-back pointer was not reset when the Tx queue was reset. This
leads to the wrong Tx desc free logic. Move the resetting of pointer into
txq->ops->reset(txq).

Fixes: 8ada71d0bb7f ("net/txgbe: add Tx head write-back mode for Amber-Lite")

Signed-off-by: Zaiyu Wang <zaiyuwang at trustnetic.com>
---
 drivers/net/txgbe/txgbe_rxtx.c            | 45 +++++++++++++----------
 drivers/net/txgbe/txgbe_rxtx.h            |  1 +
 drivers/net/txgbe/txgbe_rxtx_vec_common.h |  7 ++++
 3 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/drivers/net/txgbe/txgbe_rxtx.c b/drivers/net/txgbe/txgbe_rxtx.c
index def7c3baf0..0003fa3a3a 100644
--- a/drivers/net/txgbe/txgbe_rxtx.c
+++ b/drivers/net/txgbe/txgbe_rxtx.c
@@ -2314,4 +2314,10 @@ txgbe_reset_tx_queue(struct txgbe_tx_queue *txq)
 	txq->tx_tail = 0;
 
+	/* Zero out headwb_mem memory */
+	if (txq->headwb_mem) {
+		for (i = 0; i < txq->headwb_size; i++)
+			txq->headwb_mem[i] = 0;
+	}
+
 	/*
 	 * Always allow 1 descriptor to be un-allocated to avoid
@@ -2413,5 +2419,5 @@ txgbe_get_tx_port_offloads(struct rte_eth_dev *dev)
 }
 
-static int
+static void
 txgbe_setup_headwb_resources(struct rte_eth_dev *dev,
 					void *tx_queue,
@@ -2421,12 +2427,13 @@ txgbe_setup_headwb_resources(struct rte_eth_dev *dev,
 	const struct rte_memzone *headwb;
 	struct txgbe_tx_queue *txq = tx_queue;
-	u8 i, headwb_size = 0;
+	u8 headwb_size = 0;
 
-	if (hw->mac.type != txgbe_mac_aml && hw->mac.type != txgbe_mac_aml40) {
-		txq->headwb_mem = NULL;
-		return 0;
-	}
+	if (hw->mac.type != txgbe_mac_aml && hw->mac.type != txgbe_mac_aml40)
+		goto out;
 
-	headwb_size = hw->devarg.tx_headwb_size;
+	if (!hw->devarg.tx_headwb)
+		goto out;
+
+	headwb_size = txq->headwb_size;
 	headwb = rte_eth_dma_zone_reserve(dev, "tx_headwb_mem", txq->queue_id,
 			sizeof(u32) * headwb_size,
@@ -2434,7 +2441,8 @@ txgbe_setup_headwb_resources(struct rte_eth_dev *dev,
 
 	if (headwb == NULL) {
-		DEBUGOUT("Fail to setup headwb resources: no mem");
-		txgbe_tx_queue_release(txq);
-		return -ENOMEM;
+		PMD_DRV_LOG(INFO,
+			    "Failed to allocate headwb memory for Tx queue %u, change to SP mode",
+			    txq->queue_id);
+		goto out;
 	}
 
@@ -2442,10 +2450,8 @@ txgbe_setup_headwb_resources(struct rte_eth_dev *dev,
 	txq->headwb_dma = TMZ_PADDR(headwb);
 	txq->headwb_mem = (RTE_ATOMIC(uint32_t) *)TMZ_VADDR(headwb);
+	return;
 
-	/* Zero out headwb_mem memory */
-	for (i = 0; i < headwb_size; i++)
-		txq->headwb_mem[i] = 0;
-
-	return 0;
+out:
+	txq->headwb_mem = NULL;
 }
 
@@ -2543,4 +2549,5 @@ txgbe_dev_tx_queue_setup(struct rte_eth_dev *dev,
 	txq->ops = &def_txq_ops;
 	txq->tx_deferred_start = tx_conf->tx_deferred_start;
+	txq->headwb_size = hw->devarg.tx_headwb_size;
 #ifdef RTE_LIB_SECURITY
 	txq->using_ipsec = !!(dev->data->dev_conf.txmode.offloads &
@@ -2578,6 +2585,5 @@ txgbe_dev_tx_queue_setup(struct rte_eth_dev *dev,
 	txgbe_set_tx_function(dev, txq);
 
-	if (hw->devarg.tx_headwb)
-		err = txgbe_setup_headwb_resources(dev, txq, socket_id);
+	txgbe_setup_headwb_resources(dev, txq, socket_id);
 
 	txq->ops->reset(txq);
@@ -4752,6 +4758,5 @@ txgbe_dev_tx_init(struct rte_eth_dev *dev)
 		wr32(hw, TXGBE_TXWP(txq->reg_idx), 0);
 
-		if ((hw->mac.type == txgbe_mac_aml || hw->mac.type == txgbe_mac_aml40) &&
-		     hw->devarg.tx_headwb) {
+		if (txq->headwb_mem) {
 			uint32_t txdctl;
 
@@ -4760,5 +4765,5 @@ txgbe_dev_tx_init(struct rte_eth_dev *dev)
 			wr32(hw, TXGBE_PX_TR_HEAD_ADDRH(txq->reg_idx),
 				(uint32_t)(txq->headwb_dma >> 32));
-			if (hw->devarg.tx_headwb_size == 16)
+			if (txq->headwb_size == 16)
 				txdctl = TXGBE_PX_TR_CFG_HEAD_WB |
 					 TXGBE_PX_TR_CFG_HEAD_WB_64BYTE;
diff --git a/drivers/net/txgbe/txgbe_rxtx.h b/drivers/net/txgbe/txgbe_rxtx.h
index 9b0fffae8e..e125eb7034 100644
--- a/drivers/net/txgbe/txgbe_rxtx.h
+++ b/drivers/net/txgbe/txgbe_rxtx.h
@@ -417,4 +417,5 @@ struct txgbe_tx_queue {
 	bool		    resetting;
 	const struct rte_memzone *headwb;
+	uint16_t             headwb_size;
 	uint64_t             headwb_dma;
 	RTE_ATOMIC(uint32_t) *headwb_mem;
diff --git a/drivers/net/txgbe/txgbe_rxtx_vec_common.h b/drivers/net/txgbe/txgbe_rxtx_vec_common.h
index 77d7ff785b..6e561aff30 100644
--- a/drivers/net/txgbe/txgbe_rxtx_vec_common.h
+++ b/drivers/net/txgbe/txgbe_rxtx_vec_common.h
@@ -253,4 +253,11 @@ _txgbe_reset_tx_queue_vec(struct txgbe_tx_queue *txq)
 
 	txq->tx_tail = 0;
+
+	/* Zero out headwb_mem memory */
+	if (txq->headwb_mem) {
+		for (i = 0; i < txq->headwb_size; i++)
+			txq->headwb_mem[i] = 0;
+	}
+
 	/*
 	 * Always allow 1 descriptor to be un-allocated to avoid
-- 
2.55.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2026-07-30 10:16:02.050955792 +0100
+++ 0018-net-txgbe-fix-Tx-write-back-pointer-reset.patch	2026-07-30 10:16:01.453990798 +0100
@@ -1 +1 @@
-From a3750e3057e0f22a746da7f92e25f855fb28ab44 Mon Sep 17 00:00:00 2001
+From 0dfbe9c7e9befa9e54b4e341cf1bf96ea35a0d84 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit a3750e3057e0f22a746da7f92e25f855fb28ab44 ]
+
@@ -11 +12,0 @@
-Cc: stable at dpdk.org
@@ -21 +22 @@
-index 42baaa3ab1..22a80e5553 100644
+index def7c3baf0..0003fa3a3a 100644
@@ -102 +103 @@
-@@ -4756,6 +4762,5 @@ txgbe_dev_tx_init(struct rte_eth_dev *dev)
+@@ -4752,6 +4758,5 @@ txgbe_dev_tx_init(struct rte_eth_dev *dev)
@@ -110 +111 @@
-@@ -4764,5 +4769,5 @@ txgbe_dev_tx_init(struct rte_eth_dev *dev)
+@@ -4760,5 +4765,5 @@ txgbe_dev_tx_init(struct rte_eth_dev *dev)