Index: if_vmx.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/if_vmx.c,v
diff -u -p -r1.92 if_vmx.c
--- if_vmx.c	5 Mar 2025 06:51:25 -0000	1.92
+++ if_vmx.c	15 Jun 2025 21:24:19 -0000
@@ -1635,7 +1635,7 @@ vmxnet3_start(struct ifqueue *ifq)
 	struct vmxnet3_softc *sc = ifp->if_softc;
 	struct vmxnet3_txqueue *tq = ifq->ifq_softc;
 	struct vmxnet3_txring *ring = &tq->cmd_ring;
-	struct vmxnet3_txdesc *txd, *sop;
+	struct vmxnet3_txdesc *txd, *sor, *sop;
 	bus_dmamap_t map;
 	unsigned int prod, free, i;
 	unsigned int post = 0;
@@ -1656,12 +1656,16 @@ vmxnet3_start(struct ifqueue *ifq)
 	    0, VMX_DMA_LEN(&ring->dmamem), BUS_DMASYNC_POSTWRITE);
 
 	rgen = ring->gen;
+	gen = rgen ^ VMX_TX_GEN;
+	sor = &ring->txd[prod];
 
 	for (;;) {
 		int hdrlen;
 
-		if (free <= NTXSEGS)
+		if (free <= NTXSEGS + 1) {
+			ifq_set_oactive(ifq);
 			break;
+		}
 
 		m = ifq_dequeue(ifq);
 		if (m == NULL)
@@ -1715,11 +1719,7 @@ vmxnet3_start(struct ifqueue *ifq)
 		    map->dm_mapsize, BUS_DMASYNC_PREWRITE);
 
 		free -= map->dm_nsegs;
-		/* set oactive here since txintr may be triggered in parallel */
-		if (free <= NTXSEGS)
-			ifq_set_oactive(ifq);
 
-		gen = rgen ^ VMX_TX_GEN;
 		sop = &ring->txd[prod];
 		for (i = 0; i < map->dm_nsegs; i++) {
 			txd = &ring->txd[prod];
@@ -1739,14 +1739,18 @@ vmxnet3_start(struct ifqueue *ifq)
 
 		vmxnet3_tx_offload(sop, m);
 
+		post = 1;
+	}
+
+	if (post) {
+		ring->gen = rgen;
 		ring->prod = prod;
+
 		/* Change the ownership by flipping the "generation" bit */
 		bus_dmamap_sync(sc->sc_dmat, VMX_DMA_MAP(&ring->dmamem),
 		    0, VMX_DMA_LEN(&ring->dmamem),
 		    BUS_DMASYNC_PREWRITE|BUS_DMASYNC_POSTWRITE);
-		sop->tx_word2 ^= VMX_TX_GEN;
-
-		post = 1;
+		sor->tx_word2 ^= VMX_TX_GEN;
 	}
 
 	bus_dmamap_sync(sc->sc_dmat, VMX_DMA_MAP(&ring->dmamem),
@@ -1754,8 +1758,6 @@ vmxnet3_start(struct ifqueue *ifq)
 
 	if (!post)
 		return;
-
-	ring->gen = rgen;
 
 	WRITE_BAR0(sc, VMXNET3_BAR0_TXH(tq->queue), prod);
 }