Re: [PATCHv7 2/3] mac80211: add radar detection command/event

[Simon Wunderlich <simon.wunderlich@s2003.tu-chemnitz.de>]

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On Thu, Jan 31, 2013 at 05:48:22PM +0100, Johannes Berg wrote:
> > > > +void ieee80211_radar_detected(struct ieee80211_vif *vif, gfp_t gfp)
> > > > +{
> > > > +	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
> > > > +
> > > > +	trace_api_radar_detected(sdata);
> > > > +
> > > > +	/* may happen to devices which have been added but are not up */
> > > > +	if (!cfg80211_chandef_valid(&sdata->vif.bss_conf.chandef))
> > > > +		return;
> > > 
> > > Huh, what does device and up have to do with that?
> > > 
> > 
> > What I've tried:
> >  * configure 2 SSIDs in hostapd, start it
> >  * both wlan0 and wlan0-1 got created
> >  * only wlan0 comes up, wlan0-1 was rejected because of missing channel combinations
> >  * now I've injected a radar - which should be sent to wlan0 and wlan0-1
> >  * wlan0 could send the event, but wlan0-1 had no bss configured and therefore no chandef
> > 
> > I can change this comment to "may happen to devices which have currently no BSS configured",
> > maybe that it is not so confusing ...
> 
> Not sure I understand, how would the radar detected event come to an
> interface that doesn't really exist for the driver?

wlan0-1 exists and was created, but no AP was ever started - because hostapd tried
to start the AP on a DFS channel when wlan0 was already active, and thanks to our
interface combinations this is not allowed. Therefore, the vif.bss_conf.chandef is empty.

The interface does exist for the driver (interface add succeeded), but start_ap failed,
so it is a virgin AP interface.

I think this behaviour is correct like that ...

Cheers,
	Simon

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