mt76: mt76x02: fix tx reordering on rate control probing without a-mpdu

To avoid aggregating rate control probing packets with other traffic, and to
ensure that the probing rate gets used, probing packets get assigned a different
internal queueing priority.
This causes packets to be transmitted in a different order, which is compensated
by the receiver side reordering.
However, if A-MPDU is disabled, this reordering can become visible to upper
layers on the receiver side. Disable the priority change if A-MPDU is disabled.
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76x02_txrx.c

@@ -154,6 +154,7 @@ int mt76x02_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
 	struct mt76x02_dev *dev = container_of(mdev, struct mt76x02_dev, mt76);
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx_info->skb->data;
 	struct mt76x02_txwi *txwi = txwi_ptr;
+	bool ampdu = IEEE80211_SKB_CB(tx_info->skb)->flags & IEEE80211_TX_CTL_AMPDU;
 	int hdrlen, len, pid, qsel = MT_QSEL_EDCA;
 
 	if (qid == MT_TXQ_PSD && wcid && wcid->idx < 128)
@@ -172,7 +173,7 @@ int mt76x02_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
 
 	txwi->pktid = pid;
 
-	if (mt76_is_skb_pktid(pid))
+	if (mt76_is_skb_pktid(pid) && ampdu)
 		qsel = MT_QSEL_MGMT;
 
 	tx_info->info = FIELD_PREP(MT_TXD_INFO_QSEL, qsel) |

drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c

@@ -79,6 +79,7 @@ int mt76x02u_tx_prepare_skb(struct mt76_dev *mdev, void *data,
 	struct mt76x02_dev *dev = container_of(mdev, struct mt76x02_dev, mt76);
 	int pid, len = tx_info->skb->len, ep = q2ep(mdev->q_tx[qid].q->hw_idx);
 	struct mt76x02_txwi *txwi;
+	bool ampdu = IEEE80211_SKB_CB(tx_info->skb)->flags & IEEE80211_TX_CTL_AMPDU;
 	enum mt76_qsel qsel;
 	u32 flags;
 
@@ -97,7 +98,7 @@ int mt76x02u_tx_prepare_skb(struct mt76_dev *mdev, void *data,
 
 	txwi->pktid = pid;
 
-	if (mt76_is_skb_pktid(pid) || ep == MT_EP_OUT_HCCA)
+	if ((mt76_is_skb_pktid(pid) && ampdu) || ep == MT_EP_OUT_HCCA)
 		qsel = MT_QSEL_MGMT;
 	else
 		qsel = MT_QSEL_EDCA;