Re: [PATCH v2 2/2] mac80211: passively scan DFS channels if requested

[Antonio Quartulli <a@unstable.cc>]

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On Fri, Nov 20, 2015 at 08:52:32PM +0800, Antonio Quartulli wrote:
> On 20/11/15 18:49, Johannes Berg wrote:
> > 
> >> @@ -599,7 +599,9 @@ static int __ieee80211_start_scan(struct
> >> ieee80211_sub_if_data *sdata,
> >>  
> >>  		if ((req->channels[0]->flags &
> >>  		     IEEE80211_CHAN_NO_IR) ||
> >> -		    !req->n_ssids) {
> >> +		    !req->n_ssids ||
> >> +		    ((req->channels[0]->flags &
> >> IEEE80211_CHAN_RADAR) &&
> >> +		     (req->flags &
> >> NL80211_SCAN_FLAG_PASSIVE_RADAR))) {
> >>  			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
> >>
> > 
> > I don't really see any circumstances under which it's valid to actively
> > scan radar channels ... seems like we should do this unconditionally?
> 
> I think it would be reasonable only if the target channel is the one we
> are using and we have done CSA. But when scanning non-operative channels
> I don't think this could work.
> 
> As discussed on IRC I'd rather go for passively scanning any DFS channel.
> 
> Cheers,

Hey Johannes,

this has been sleeping for a while.. :)
Would it make sense to rebase it and resubmit it for inclusion?

Given the previous discussion we could change the logic as:
* always passively scan DFS channels that are not usable
* always actively scan DFS channels that are usable (i.e. CAC was performed).

How does it sound? this would totally avoid the use of the switch in the scan
command.

Cheers,


-- 
Antonio Quartulli

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