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Commit 6986fdd6 authored by Michal Kazior's avatar Michal Kazior Committed by Kalle Valo
Browse files

ath10k: fix mu-mimo rx status reporting 



MU-MIMO Rx involves different interpretation of
the VHT-SIG-A compared to SU-MIMO.

The incorrect interpretation led ath10k to report
VHT MCS values greater than 9 which subsequently
prompted mac80211 to drop such frames. This
effectively broke Rx with MU-MIMO in many cases
and manifested with a kernel warning in the log
which looked like this:

  [   14.552520] WARNING: CPU: 2 PID: 0 at net/mac80211/rx.c:3578 ieee80211_rx+0x26c/0x940 [mac80211]()
  [   14.552522] Rate marked as a VHT rate but data is invalid: MCS: 10, NSS: 2
  ... call trace follows ...

Signed-off-by: default avatarMichal Kazior <michal.kazior@tieto.com>
Signed-off-by: default avatarKalle Valo <kvalo@qca.qualcomm.com>
parent ee92a209

drivers/net/wireless/ath/ath10k/htt_rx.c

+22 −2
Original line number Diff line number Diff line
@@ -643,6 +643,8 @@ struct amsdu_subframe_hdr { 
	__be16 len;

} __packed;



#define GROUP_ID_IS_SU_MIMO(x) ((x) == 0 || (x) == 63)



static void ath10k_htt_rx_h_rates(struct ath10k *ar,

				  struct ieee80211_rx_status *status,

				  struct htt_rx_desc *rxd)
@@ -650,6 +652,7 @@ static void ath10k_htt_rx_h_rates(struct ath10k *ar, 
	struct ieee80211_supported_band *sband;

	u8 cck, rate, bw, sgi, mcs, nss;

	u8 preamble = 0;

	u8 group_id;

	u32 info1, info2, info3;



	info1 = __le32_to_cpu(rxd->ppdu_start.info1);
@@ -692,10 +695,27 @@ static void ath10k_htt_rx_h_rates(struct ath10k *ar, 
	case HTT_RX_VHT_WITH_TXBF:

		/* VHT-SIG-A1 in info2, VHT-SIG-A2 in info3

		   TODO check this */

		mcs = (info3 >> 4) & 0x0F;

		nss = ((info2 >> 10) & 0x07) + 1;

		bw = info2 & 3;

		sgi = info3 & 1;

		group_id = (info2 >> 4) & 0x3F;



		if (GROUP_ID_IS_SU_MIMO(group_id)) {

			mcs = (info3 >> 4) & 0x0F;

			nss = ((info2 >> 10) & 0x07) + 1;

		} else {

			/* Hardware doesn't decode VHT-SIG-B into Rx descriptor

			 * so it's impossible to decode MCS. Also since

			 * firmware consumes Group Id Management frames host

			 * has no knowledge regarding group/user position

			 * mapping so it's impossible to pick the correct Nsts

			 * from VHT-SIG-A1.

			 *

			 * Bandwidth and SGI are valid so report the rateinfo

			 * on best-effort basis.

			 */

			mcs = 0;

			nss = 1;

		}



		status->rate_idx = mcs;

		status->vht_nss = nss;