Re: [wireless-regdb] [RFC] wireless-regdb: Update 5 GHz rules for Canada

[Seth Forshee <seth.forshee@canonical.com>]

There were some replies to this, but I just noticed that the mailing
list somehow got dropped. Bringing the discussion back to the list.

On Mon, Feb 13, 2017 at 02:58:28PM +0100, Matthias May wrote:
> On 07/02/17 15:04, Seth Forshee wrote:
> > On Tue, Feb 07, 2017 at 08:52:30AM +0100, Johannes Berg wrote:
> >> On Mon, 2017-02-06 at 14:50 -0600, Seth Forshee wrote:
> >>> +	(5150 - 5250 @ 80), (23), AUTO-BW
> >>
> >> For 20 MHz this is right, since the document says:
> >>
> >>     The maximum e.i.r.p. shall not exceed 200 mW or 10 + 10 log10 B,
> >>     dBm, whichever power is less. B is the 99% emission bandwidth in
> >>     megahertz. The e.i.r.p. spectral density shall not exceed 10 dBm in
> >>     any 1.0 MHz band.
> >>
> >> However, for < 20 MHz, like 5 or 10, which we in theory do support, you
> >> can't use that much due to the spectral density requirement. It seems
> >> possible that that's where the 17 dBm came from, since 10 + 10 log10(5)
> >> is about 17.
> > 
> > Yes, thanks. I had forgotten to consider bandwidths less than 20 MHz.
> > 
> > Seth
> > 
> > _______________________________________________
> > wireless-regdb mailing list
> > wireless-regdb@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/wireless-regdb
> > 
> 
> According to  .../include/net/cfg80211.h
> 
> >static inline int
> >ieee80211_chandef_max_power(struct cfg80211_chan_def *chandef)
> >{
> >	switch (chandef->width) {
> >	case NL80211_CHAN_WIDTH_5:
> >		return min(chandef->chan->max_reg_power - 6,
> >			   chandef->chan->max_power);
> >	case NL80211_CHAN_WIDTH_10:
> >		return min(chandef->chan->max_reg_power - 3,
> >			   chandef->chan->max_power);
> >	default:
> >		break;
> >	}
> >	return chandef->chan->max_power;
> >}
> 
> This looks to me like it already handles the reduction of power
> according to bandwidth.

Johannes, just wanted to confirm that based on this you no longer have
any objection to the changes.

Thanks,
Seth

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