[report] wifi: mt76: mt7996: fix FCS error flag check in RX descriptor

[Peter Chiu]

On Sun, 2025-10-12 at 22:02 +0530, ALOK TIWARI wrote:

Hi Alok,

Thanks for your mail.
Your understanding is correct.
There is a typo in mt7996.

Thanks,
Peter Chiu

> 
> External email : Please do not click links or open attachments until
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> 
> 
> Hi,
> 
> While looking through the FCS error handling in the mt76 drivers,
> I noticed that mt7996 uses rxd1 to check the MT_RXD3_NORMAL_FCS_ERR
> bit,
> whereas other Connac3-based drivers (such as mt7925) use rxd3.
> 
> According to the definitions, MT_RXD3_NORMAL_FCS_ERR is located in
> the
> fourth
> RX descriptor word (rxd3), so I prepared a small patch to switch the
> check from
> rxd1 to rxd3 for consistency and correctness.
> 
> Before sending it formally, I wanted to confirm whether this
> understanding is correct.
> is mt7996 indeed supposed to use rxd3 for this flag, like mt7925?
> 
> Fixes: 98686cd21624 ("wifi: mt76: mt7996: add driver for MediaTek Wi-
> Fi
> 7 (802.11be) devices")
> 
> Thanks,
> Alok
> 
> ---
>   drivers/net/wireless/mediatek/mt76/mt7996/mac.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
> b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
> index 9501def3e0e3..59744e5593b6 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
> @@ -527,7 +527,7 @@ mt7996_mac_fill_rx(struct mt7996_dev *dev, enum
> mt76_rxq_id q,
>              !(csum_status & (BIT(0) | BIT(2) | BIT(3))))
>                  skb->ip_summed = CHECKSUM_UNNECESSARY;
> 
> -       if (rxd1 & MT_RXD3_NORMAL_FCS_ERR)
> +       if (rxd3 & MT_RXD3_NORMAL_FCS_ERR)
>                  status->flag |= RX_FLAG_FAILED_FCS_CRC;
> 
>          if (rxd1 & MT_RXD1_NORMAL_TKIP_MIC_ERR)
> --
> 2.50.1