[PATCH ath-next 1/2] wifi: ath11k: don't bit-reverse the firmware's PPE thresholds

[Rameshkumar Sundaram]

On 11/5/2026 10:47 AM, Christopher Griffin via B4 Relay wrote:
> From: Christopher Griffin <christophergriffin05 at gmail.com>
> 
> The firmware reports its PPE thresholds as WMI defines them: in
> ppet16_ppet8_ru3_ru0[nss], each RU has six bits, PPET16 in bits 2:0 and
> PPET8 in bits 5:3, each a 3-bit constellation index. The PPE Thresholds
> field of the HE Capabilities element carries the same two subfields in
> the same order, bit 0 first, and ath11k_peer_assoc_h_he() already

yes, but ath11k_peer_assoc_h_he() logic seems to be too complicated as 
well with << 5 and >> 1 for each iteration. Looks we need to simplify 
that with just,

val |= ((he_cap->ppe_thres[bit / 8] >> (bit % 8)) & 0x1) << i;

May be in a separate patch.


> converts a peer's field to the WMI layout that way.
> 
> ath11k_gen_ppe_thresh(), which builds our own field from the firmware's,
> swaps the two halves and then writes the six bits from the top down.
> That puts PPET16 first again, but with its three bits reversed, and the
> same for PPET8: a threshold of 1 (QPSK) is advertised as 4 (256-QAM),
> 4 as 1, 3 (64-QAM) as 6 (reserved) and 6 as 3. Only 0, 2, 5 and 7 (none)
> come out right, so the bug does not show with firmware that asks for
> 16 us padding at every constellation (PPET16 0, PPET8 7).
> 
> Copy the six bits in order.
> 
> IPQ8074 (WLAN.HK.2.9.0.1-02146) and QCN9074 (WLAN.HK.2.5.r4-00683)
> firmware report PPET16 0 and PPET8 7 everywhere (iw phy: PPE Threshold
> 0x7b 0x1c 0xc7 0x71 ...), which reads the same either way, so their HE
> capabilities do not change. Compile-tested.
> 
> Fixes: 9f056ed8ee01 ("ath11k: add HE support")
> Assisted-by: Claude:claude-opus-5-5

This tag may not be needed as per latest guidelines

> Signed-off-by: Christopher Griffin <christophergriffin05 at gmail.com>
> ---
>   drivers/net/wireless/ath/ath11k/mac.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
> index 1a237adaa37d1..8b4e992b609a6 100644
> --- a/drivers/net/wireless/ath/ath11k/mac.c
> +++ b/drivers/net/wireless/ath/ath11k/mac.c
> @@ -5825,8 +5825,7 @@ static void ath11k_gen_ppe_thresh(struct ath11k_ppe_threshold *fw_ppet,
>   				continue;
>   			val = (fw_ppet->ppet16_ppet8_ru3_ru0[nss] >> (ru * 6)) &
>   			       0x3f;
> -			val = ((val >> 3) & 0x7) | ((val & 0x7) << 3);
> -			for (i = 5; i >= 0; i--) {
> +			for (i = 0; i < 6; i++) {
>   				he_ppet[bit / 8] |=
>   					((val >> i) & 0x1) << ((bit % 8));
>   				bit++;
> 
-- 
Ramesh