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

[Antonio Quartulli <antonio@open-mesh.com>]

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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,


-- 
Antonio Quartulli


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