From: Johannes Berg Date: Fri, 9 May 2014 07:56:53 +0000 (+0200) Subject: mac80211: allow VHT with peers not capable of 40MHz X-Git-Tag: accepted/tizen/common/20141203.182822~94^2~51^2~23^2^2~4^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4a817aa78f573c6964f16d9aea3d0d10a226ade4;p=platform%2Fkernel%2Flinux-arm64.git mac80211: allow VHT with peers not capable of 40MHz There are two (related) issues with this. One case, reported by Michal, is related to hostap: it unsets the 20/40 capability bit for stations that associate when it's in 20 MHz mode. The other case, reported by Eyal, is that some APs like Netgear R6300v2 and probably others based on the BCM4360 chipset can be configured for doing VHT at 20Mhz. In this case the beacon has a VHT IE but the HT cap indicates transmitter only support 20Mhz. In both of these cases, we currently avoid VHT and use only HT this means we can't use the highest rates (MCS8), so fixing this leads to throughput improvements. Reported-by: Michal Kazior Reported-by: Eyal Shapira Signed-off-by: Johannes Berg --- diff --git a/net/mac80211/vht.c b/net/mac80211/vht.c index e9e36a2..9265adf 100644 --- a/net/mac80211/vht.c +++ b/net/mac80211/vht.c @@ -129,9 +129,12 @@ ieee80211_vht_cap_ie_to_sta_vht_cap(struct ieee80211_sub_if_data *sdata, if (!vht_cap_ie || !sband->vht_cap.vht_supported) return; - /* A VHT STA must support 40 MHz */ - if (!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40)) - return; + /* + * A VHT STA must support 40 MHz, but if we verify that here + * then we break a few things - some APs (e.g. Netgear R6300v2 + * and others based on the BCM4360 chipset) will unset this + * capability bit when operating in 20 MHz. + */ vht_cap->vht_supported = true;