@@ -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;
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: Michal Kazior <michal.kazior@tieto.com> --- drivers/net/wireless/ath/ath10k/htt_rx.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)