diff options
| author | Jouni Malinen <jouni@qca.qualcomm.com> | 2016-02-01 11:40:55 +0200 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2016-02-24 09:04:32 +0100 |
| commit | 23665aaf9170ae6328cc4f68250c529a628af2ab (patch) | |
| tree | cd4cefd66e788a04d15ebc4bc4ca92863eac3011 /net/mac80211/util.c | |
| parent | 06470f7468c8b6c95e72ebda803a61a99f4ee446 (diff) | |
| download | blackbird-obmc-linux-23665aaf9170ae6328cc4f68250c529a628af2ab.tar.gz blackbird-obmc-linux-23665aaf9170ae6328cc4f68250c529a628af2ab.zip | |
mac80211: Interoperability workaround for 80+80 and 160 MHz channels
Number of deployed 80 MHz capable VHT stations that do not support 80+80
and 160 MHz bandwidths seem to misbehave when trying to connect to an AP
that advertises 80+80 or 160 MHz channel bandwidth in the VHT Operation
element. To avoid such issues with deployed devices, modify the design
based on recently accepted IEEE 802.11 standard changes (*).
This allows poorly implemented VHT 80 MHz stations to connect with the
AP in 80 MHz mode. 80+80 and 160 MHz capable stations need to support
the new workaround mechanism to allow full bandwidth to be used.
However, there are more or less no impacted station with 80+80/160
capability deployed.
The rebased version of this patch is based on the updated version from
Johannes Berg to take the HT/VHT chandef refactoring into account.
(*) Changes in
https://mentor.ieee.org/802.11/dcn/15/11-15-1530-04-000m-vht160-operation-signaling-through-non-zero-ccfs1.docx
were accepted during the IEEE 802.11 January 2016 meeting.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/util.c')
| -rw-r--r-- | net/mac80211/util.c | 31 |
1 files changed, 29 insertions, 2 deletions
diff --git a/net/mac80211/util.c b/net/mac80211/util.c index 091f3dd62ad1..f1e5b76eda70 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -2364,10 +2364,23 @@ u8 *ieee80211_ie_build_vht_oper(u8 *pos, struct ieee80211_sta_vht_cap *vht_cap, switch (chandef->width) { case NL80211_CHAN_WIDTH_160: - vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_160MHZ; + /* + * Convert 160 MHz channel width to new style as interop + * workaround. + */ + vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_80MHZ; + vht_oper->center_freq_seg2_idx = vht_oper->center_freq_seg1_idx; + if (chandef->chan->center_freq < chandef->center_freq1) + vht_oper->center_freq_seg1_idx -= 8; + else + vht_oper->center_freq_seg1_idx += 8; break; case NL80211_CHAN_WIDTH_80P80: - vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_80P80MHZ; + /* + * Convert 80+80 MHz channel width to new style as interop + * workaround. + */ + vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_80MHZ; break; case NL80211_CHAN_WIDTH_80: vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_80MHZ; @@ -2430,6 +2443,20 @@ bool ieee80211_chandef_vht_oper(const struct ieee80211_vht_operation *oper, case IEEE80211_VHT_CHANWIDTH_80MHZ: new.width = NL80211_CHAN_WIDTH_80; new.center_freq1 = cf1; + /* If needed, adjust based on the newer interop workaround. */ + if (oper->center_freq_seg2_idx) { + unsigned int diff; + + diff = abs(oper->center_freq_seg2_idx - + oper->center_freq_seg1_idx); + if (diff == 8) { + new.width = NL80211_CHAN_WIDTH_160; + new.center_freq1 = cf2; + } else if (diff > 8) { + new.width = NL80211_CHAN_WIDTH_80P80; + new.center_freq2 = cf2; + } + } break; case IEEE80211_VHT_CHANWIDTH_160MHZ: new.width = NL80211_CHAN_WIDTH_160; |
