Since multiple net_device TX queues can share the same hw QDMA TX queue, there is no guarantee we have inflight packets queued in hw belonging to a net_device TX queue stopped in the xmit path because hw QDMA TX queue can be full. In this corner case the net_device TX queue will never be re-activated. In order to avoid any potential net_device TX queue stall, we need to wake all the net_device TX queues feeding the same hw QDMA TX queue in airoha_qdma_tx_napi_poll routine. Fixes: 23020f0493270 ("net: airoha: Introduce ethernet support for EN7581 SoC") Signed-off-by: Lorenzo Bianconi --- drivers/net/ethernet/airoha/airoha_eth.c | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c index 9e995094c32a..e7610f36b8e4 100644 --- a/drivers/net/ethernet/airoha/airoha_eth.c +++ b/drivers/net/ethernet/airoha/airoha_eth.c @@ -855,6 +855,19 @@ static int airoha_qdma_init_rx(struct airoha_qdma *qdma) return 0; } +static void airoha_qdma_wake_tx_queues(struct airoha_qdma *qdma) +{ + struct airoha_eth *eth = qdma->eth; + int i; + + for (i = 0; i < ARRAY_SIZE(eth->ports); i++) { + struct airoha_gdm_port *port = eth->ports[i]; + + if (port && port->qdma == qdma) + netif_tx_wake_all_queues(port->dev); + } +} + static int airoha_qdma_tx_napi_poll(struct napi_struct *napi, int budget) { struct airoha_tx_irq_queue *irq_q; @@ -931,12 +944,21 @@ static int airoha_qdma_tx_napi_poll(struct napi_struct *napi, int budget) txq = netdev_get_tx_queue(skb->dev, queue); netdev_tx_completed_queue(txq, 1, skb->len); - if (netif_tx_queue_stopped(txq) && - q->ndesc - q->queued >= q->free_thr) - netif_tx_wake_queue(txq); - dev_kfree_skb_any(skb); } + + if (q->ndesc - q->queued == q->free_thr) { + /* Since multiple net_device TX queues can share the + * same hw QDMA TX queue, there is no guarantee we have + * inflight packets queued in hw belonging to a + * net_device TX queue stopped in the xmit path. + * In order to avoid any potential net_device TX queue + * stall, we need to wake all the net_device TX queues + * feeding the same hw QDMA TX queue. + */ + airoha_qdma_wake_tx_queues(qdma); + } + unlock: spin_unlock_bh(&q->lock); } --- base-commit: 2dddb34dd0d07b01fa770eca89480a4da4f13153 change-id: 20260407-airoha-txq-potential-stall-ad52c53094e8 Best regards, -- Lorenzo Bianconi