• Filip Matusiak's avatar
    mac80211: Ignore VHT IE from peer with wrong rx_mcs_map · c8eaf347
    Filip Matusiak authored
    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, an example is AR9462 in AP mode.
    
    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.
    
    Some devices in STA mode will get firmware assert when trying to
    associate, examples are QCA9377 & QCA6174.
    
    Packet example of broken VHT Cap IE of AR9462:
    
    Tag: VHT Capabilities (IEEE Std 802.11ac/D3.1)
        Tag Number: VHT Capabilities (IEEE Std 802.11ac/D3.1) (191)
        Tag length: 12
        VHT Capabilities Info: 0x00000000
        VHT Supported MCS Set
            Rx MCS Map: 0xffff
                .... .... .... ..11 = Rx 1 SS: Not Supported (0x0003)
                .... .... .... 11.. = Rx 2 SS: Not Supported (0x0003)
                .... .... ..11 .... = Rx 3 SS: Not Supported (0x0003)
                .... .... 11.. .... = Rx 4 SS: Not Supported (0x0003)
                .... ..11 .... .... = Rx 5 SS: Not Supported (0x0003)
                .... 11.. .... .... = Rx 6 SS: Not Supported (0x0003)
                ..11 .... .... .... = Rx 7 SS: Not Supported (0x0003)
                11.. .... .... .... = Rx 8 SS: Not Supported (0x0003)
            ...0 0000 0000 0000 = Rx Highest Long GI Data Rate (in Mb/s, 0 = subfield not in use): 0x0000
            Tx MCS Map: 0xffff
            ...0 0000 0000 0000 = Tx Highest Long GI Data Rate  (in Mb/s, 0 = subfield not in use): 0x0000
    Signed-off-by: default avatarFilip Matusiak <filip.matusiak@tieto.com>
    Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
    c8eaf347
vht.c 16.4 KB