[wireless-regdb] [PATCH] regdb: allow 40 MHz on world roaming channels 12/13

[Johannes Berg]

On Tue, 2012-12-04 at 10:13 -0800, Luis R. Rodriguez wrote:

> >> When in world roaming mode, allow 40 MHz to be used
> >> on channels 12 and 13 so that an AP that is, e.g.,
> >> using HT40+ on channel 9 (in the UK) can be used.
> >
> > Well, hold on.. this can't possibly work now :(
> >
> > This is what happens when Luis and I disagree ...
> >
> > I thought the bandwidth in a given section means the bandwidth that can
> > be used from this section,
> 
> No, indeed that was the objective.

That's not what's implemented though.

> > Luis implemented it to mean that a channel
> > overlapping any part of that section can only use that much bandwidth.
> 
> This was a side effect of the checks we have in place, it was not expected.

But this is what happens due to the reg.c implementation -- it checks
that the freqband into which the primary and secondary channel fall each
allows 40 MHz, even if they are two different freqbands.

> > Note sure which was intended?
> 
> Technically speaking the math should be possible to figure out to
> enable HT40 or not based on peer channels and although that was
> assumed the user reported it not allowing HT40 due to the peer
> channels not allowing HT40. I took your patch as an assumption that
> was not possible.

Indeed this is what we had, but I built the db.txt parser based on the
assumption that in fact "@ 20" in the channel 11/12 freqband would have
been sufficient to allow 40 Mhz on channel 9+. This isn't the case in
the kernel implementation today.

johannes