> When the hardware falls back to lower rates for a transmit attempt, only the > first status report will show the number of retries correctly. The frames > that follow will report the correct final rate, but number of retries set to > 0. > This can cause the rate control module to vastly underestimate the number of > retransmissions per rate. > > To fix this, we need to keep track of the initial requested tx rate per packet > and pass it to the status information. > For frames with tx status requested, this is simple: use the rate configured > in info->control.rates[0] as reference. > For no-skb tx status information, we have to encode the requested tx rate in > the packet id (and make it possible to distinguish it from real packet ids). > > To do that, reduce the packet id field size by one bit, and use that bit to > indicate packet id vs rate. > > This change also improves reporting by filling the status rate array with > rates from first rate to final rate, taking the same steps as the hardware > fallback table. This matters in corner cases like MCS8 on HT, where the > fallback target is MCS0, not MCS7. >
[...]
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_txrx.c
> b/drivers/net/wireless/mediatek/mt76/mt76x02_txrx.c
> index cf7abd9b7d2e..95c73049a68b 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x02_txrx.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_txrx.c
> @@ -164,9 +164,14 @@ int mt76x02_tx_prepare_skb(struct mt76_dev *mdev, void
> *txwi_ptr,
> mt76x02_mac_write_txwi(dev, txwi, tx_info->skb, wcid, sta, len);
>
> pid = mt76_tx_status_skb_add(mdev, wcid, tx_info->skb);
> +
> + /* encode packet rate for no-skb packet id to fix up status reporting */
> + if (pid == MT_PACKET_ID_NO_SKB)
> + pid = MT_PACKET_ID_HAS_RATE | (txwi->rate & MT_RXWI_RATE_INDEX);
I guess here we should do:
pid = MT_PACKET_ID_HAS_RATE | (le16_to_cpu(txwi->rate) &
MT_RXWI_RATE_INDEX);
> +
> txwi->pktid = pid;
>
> - if (pid >= MT_PACKET_ID_FIRST)
> + if (mt76_is_skb_pktid(pid))
> qsel = MT_QSEL_MGMT;
>
> tx_info->info = FIELD_PREP(MT_TXD_INFO_QSEL, qsel) |
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
> b/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
> index 6b89f7eab26c..2436f14ca24a 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
> @@ -89,9 +89,14 @@ int mt76x02u_tx_prepare_skb(struct mt76_dev *mdev, void
> *data,
> skb_push(tx_info->skb, sizeof(*txwi));
>
> pid = mt76_tx_status_skb_add(mdev, wcid, tx_info->skb);
> +
> + /* encode packet rate for no-skb packet id to fix up status reporting */
> + if (pid == MT_PACKET_ID_NO_SKB)
> + pid = MT_PACKET_ID_HAS_RATE | (txwi->rate & MT_RXWI_RATE_INDEX);
same here
Regards,
Lorenzo
> +
> txwi->pktid = pid;
>
> - if (pid >= MT_PACKET_ID_FIRST || ep == MT_EP_OUT_HCCA)
> + if (mt76_is_skb_pktid(pid) || ep == MT_EP_OUT_HCCA)
> qsel = MT_QSEL_MGMT;
> else
> qsel = MT_QSEL_EDCA;
> --
> 2.17.0
>
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