Re: [PATCH] mac80211: Handle power constraint level advertised in 11d+h beacon

[Johannes Berg <johannes@sipsolutions.net>]

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On Mon, 2009-01-05 at 19:07 +0530, Vasanthakumar Thiagarajan wrote:

[an email that somehow was just an attachment?]

> > Also, I don't understand the subtraction? And why are you checking only
> > for sw scanning and not hw scanning?
> 
> I think driver should handle in case of hw_scanning.

Yes, true, it's all per-channel too.

> > > +
> > > +	if ((*pwr_constr_elem <= conf->channel->max_power) &&
> > > +	    (*pwr_constr_elem != conf->power_constr_level)) {
> > > +		conf->power_constr_level = *pwr_constr_elem;
> > > +		ieee80211_hw_config(sdata->local, 0);
> > 
> > That needs a changed flag, no? 
> 
> No, ieee80211_hw_config() will take care.

Indeed, my mistake.

> > And how does the subtraction make sense
> > like this? The spec talks about the country element's max power, and
> > then subtracting this, to get the local power, but if the local power
> > was set lower than that then we shouldn't subtract even more, no?
> 
> 
> This is more concervative way of processing power constraint.  Yeah, you are correct
> that we might be setting lower tx power than the allowed one when we subtract power
> constraint from already min power (of reg data base and 11d ie) instead of only power 
> limit advertised in 11d ie, but this situation is uncommon. 

Ok, makes sense, let's not worry about it then.

That means the unmodified patch is fine, I guess.

johannes

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