This is a workaround for VHT-enabled STAs which break the spec
and have the VHT-MCS Rx map filled in with value 3 for all eight
spacial streams.

As per spec, in section 22.1.1 Introduction to the VHT PHY
A VHT STA shall support at least single spactial stream VHT-MCSs
0 to 7 (transmit and receive) in all supported channel widths.

For some devices firmware asserts if such situation occurs.

Signed-off-by: Filip Matusiak <filip.matus...@tieto.com>
---
 net/mac80211/vht.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/net/mac80211/vht.c b/net/mac80211/vht.c
index ee71576..ce93cff 100644
--- a/net/mac80211/vht.c
+++ b/net/mac80211/vht.c
@@ -270,6 +270,22 @@ ieee80211_vht_cap_ie_to_sta_vht_cap(struct 
ieee80211_sub_if_data *sdata,
                vht_cap->vht_mcs.tx_mcs_map |= cpu_to_le16(peer_tx << i * 2);
        }
 
+       /*
+        * This is a workaround for VHT-enabled STAs which break the spec
+        * and have the VHT-MCS Rx map filled in with value 3 for all eight
+        * spacial streams.
+        *
+        * As per spec, in section 22.1.1 Introduction to the VHT PHY
+        * A VHT STA shall support at least single spactial stream VHT-MCSs
+        * 0 to 7 (transmit and receive) in all supported channel widths.
+        */
+       if (vht_cap->vht_mcs.rx_mcs_map == cpu_to_le16(0xFFFF)) {
+               vht_cap->vht_supported = false;
+               sdata_info(sdata, "Ignoring VHT IE from %pM due to invalid 
rx_mcs_map\n",
+                          sta->addr);
+               return;
+       }
+
        /* finally set up the bandwidth */
        switch (vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK) {
        case IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ:
-- 
2.7.4

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