Re: [PATCH] mac80211: Remove VHT Capabilities/Operation IEs from mesh beacon if VHT was disabled

[Johannes Berg <johannes@sipsolutions.net>]

> This patch removes VHT Capabilities/Operation IEs when the
> wpa_supplicant.conf includes disable_vht=1. We recognize the local
> peer
> as 11ac ready, when it has more than 80MHz band width. Because
> net/mac80211/util.c#ieee80211_build_preq_ies_band() uses 80MHz
> threshold
> for VHT Capabilities IE inclusion.

I believe this is incorrect the way you've written it, we shouldn't
disable VHT because 80 MHz isn't *used* right now.

The code you reference checks if 80 MHz was technically *supported*,
and that's really only because we otherwise can't connect to a BSS
network that supports VHT, since the AP might switch from 20/40 to
80/160, and we can't say that we don't support 80 (since we have to
support it if we support VHT.)

>  	sband = local->hw.wiphy->bands[band];
>  	if (!sband->vht_cap.vht_supported ||
> -	    sdata->vif.bss_conf.chandef.width ==
> NL80211_CHAN_WIDTH_20_NOHT ||
> -	    sdata->vif.bss_conf.chandef.width ==
> NL80211_CHAN_WIDTH_5 ||
> -	    sdata->vif.bss_conf.chandef.width ==
> NL80211_CHAN_WIDTH_10)
> +	    !(sdata->vif.bss_conf.chandef.width ==
> NL80211_CHAN_WIDTH_80 ||
> +	    sdata->vif.bss_conf.chandef.width ==
> NL80211_CHAN_WIDTH_80P80 ||
> +	    sdata->vif.bss_conf.chandef.width ==
> NL80211_CHAN_WIDTH_160))
>  		return 0;
> 

But using the current bandwidth as you do now seems incorrect to me.

johannes