[PATCH ath-next V16 1/2] wifi: ath12k: fix VHT MCS assignment

[Jeff Johnson]

On 10/1/2025 5:07 PM, Pradeep Kumar Chitrapu wrote:
> From: Baochen Qiang <baochen.qiang at oss.qualcomm.com>
> 
> While associating, firmware needs the peer's receive capability
> to calculate its own VHT transmit MCS. Currently, the host
> sends this information via mcs->rx_mcs_set field, but firmware
> actually reads it from mcs->tx_mcs_set field. Thjis mismatch is

s/Thjis/This/

> incorrect.
> 
> This issue has not caused failures so far because most peers
> advertise identical TX and RX capabilities. Fix this by
> assigning the value to tx_mcs_set as expected.
> 
> Additionally, the rate control mask is intended to limit our
> transmit MCS, so it should also apply to the peer's receive
> capability. Update the logic accordingly.
> 
> Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
> 
> Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
> Signed-off-by: Baochen Qiang <baochen.qiang at oss.qualcomm.com>
> Signed-off-by: Pradeep Kumar Chitrapu <quic_pradeepc at quicinc.com>
> ---
>  drivers/net/wireless/ath/ath12k/mac.c |  7 +++----
>  drivers/net/wireless/ath/ath12k/wmi.c | 11 +++++++----
>  drivers/net/wireless/ath/ath12k/wmi.h |  2 ++

wmi.c and wmi.h need copyright updates to match current guidance.

>  3 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
> index 1d7b60aa5cb0..0d425a1bc0ab 100644
> --- a/drivers/net/wireless/ath/ath12k/mac.c
> +++ b/drivers/net/wireless/ath/ath12k/mac.c
> @@ -2249,7 +2249,6 @@ static void ath12k_peer_assoc_h_vht(struct ath12k *ar,
>  	struct cfg80211_chan_def def;
>  	enum nl80211_band band;
>  	u16 *vht_mcs_mask;
> -	u16 tx_mcs_map;
>  	u8 ampdu_factor;
>  	u8 max_nss, vht_mcs;
>  	int i, vht_nss, nss_idx;
> @@ -2340,10 +2339,10 @@ static void ath12k_peer_assoc_h_vht(struct ath12k *ar,
>  	arg->peer_nss = min(link_sta->rx_nss, max_nss);
>  	arg->rx_max_rate = __le16_to_cpu(vht_cap->vht_mcs.rx_highest);
>  	arg->rx_mcs_set = __le16_to_cpu(vht_cap->vht_mcs.rx_mcs_map);
> -	arg->tx_max_rate = __le16_to_cpu(vht_cap->vht_mcs.tx_highest);
> +	arg->rx_mcs_set = ath12k_peer_assoc_h_vht_limit(arg->rx_mcs_set, vht_mcs_mask);
>  
> -	tx_mcs_map = __le16_to_cpu(vht_cap->vht_mcs.tx_mcs_map);
> -	arg->tx_mcs_set = ath12k_peer_assoc_h_vht_limit(tx_mcs_map, vht_mcs_mask);
> +	arg->tx_max_rate = __le16_to_cpu(vht_cap->vht_mcs.tx_highest);
> +	arg->tx_mcs_set = __le16_to_cpu(vht_cap->vht_mcs.tx_mcs_map);
>  
>  	/* In QCN9274 platform, VHT MCS rate 10 and 11 is enabled by default.
>  	 * VHT MCS rate 10 and 11 is not supported in 11ac standard.
> diff --git a/drivers/net/wireless/ath/ath12k/wmi.c b/drivers/net/wireless/ath/ath12k/wmi.c
> index ff6b3d4ea820..2682d89afd44 100644
> --- a/drivers/net/wireless/ath/ath12k/wmi.c
> +++ b/drivers/net/wireless/ath/ath12k/wmi.c
> @@ -2367,10 +2367,13 @@ int ath12k_wmi_send_peer_assoc_cmd(struct ath12k *ar,
>  	cmd->peer_bw_rxnss_override |= cpu_to_le32(arg->peer_bw_rxnss_override);
>  
>  	if (arg->vht_capable) {
> -		mcs->rx_max_rate = cpu_to_le32(arg->rx_max_rate);
> -		mcs->rx_mcs_set = cpu_to_le32(arg->rx_mcs_set);
> -		mcs->tx_max_rate = cpu_to_le32(arg->tx_max_rate);
> -		mcs->tx_mcs_set = cpu_to_le32(arg->tx_mcs_set);
> +		/* Firmware interprets mcs->tx_mcs_set field as peer's
> +		 * RX capability
> +		 */
> +		mcs->rx_max_rate = cpu_to_le32(arg->tx_max_rate);
> +		mcs->rx_mcs_set = cpu_to_le32(arg->tx_mcs_set);
> +		mcs->tx_max_rate = cpu_to_le32(arg->rx_max_rate);
> +		mcs->tx_mcs_set = cpu_to_le32(arg->rx_mcs_set);
>  	}
>  
>  	/* HE Rates */
> diff --git a/drivers/net/wireless/ath/ath12k/wmi.h b/drivers/net/wireless/ath/ath12k/wmi.h
> index a8c3190e8ad9..6d9c645e3d5d 100644
> --- a/drivers/net/wireless/ath/ath12k/wmi.h
> +++ b/drivers/net/wireless/ath/ath12k/wmi.h
> @@ -4218,8 +4218,10 @@ struct wmi_unit_test_cmd {
>  struct ath12k_wmi_vht_rate_set_params {
>  	__le32 tlv_header;
>  	__le32 rx_max_rate;
> +	/* MCS at which the peer can transmit */
>  	__le32 rx_mcs_set;
>  	__le32 tx_max_rate;
> +	/* MCS at which the peer can receive */
>  	__le32 tx_mcs_set;
>  	__le32 tx_max_mcs_nss;
>  } __packed;
I can apply my two comments when I process this series if there are no other
changes required.

/jeff