Re: [PATCH] cfg80211: VHT (11ac) Regulatory change

[Stanislaw Gruszka <sgruszka@redhat.com>]

On Wed, Aug 22, 2012 at 11:04:42AM +0200, Johannes Berg wrote:
> On Wed, 2012-08-22 at 11:01 +0200, Stanislaw Gruszka wrote:
> 
> > > Yeah but we don't have that yet. We could do it that way, sure, but it
> > > has wide-spread implications, since we'll need to
> > >  - use this new form of specifying channels all over mac80211 and all
> > >    drivers,
> > >  - define new nl80211 attributes for it,
> > >  - write new code in nl80211 to handle all this,
> > >  - and parse the old attributes into the new data structure(s) so
> > >    drivers use the new API but userspace can continue to use the old
> > > 
> > > None of that is done yet.
> > 
> > For starters (for regulatory purpose only) would be sufficient to
> > implement
> > 
> > regulatory_chan_use_permitted(center freq, bandwidth, whatever else),
> > 
> > and use it where currently IEEE80211_CHAN_NO_HT_X flags are used.
> 
> Yes, in theory. However, if this was intended to use the actual "center
> freq, bandwidth, control channel offset" values, then it would be much
> better to first actually define a struct to hold those, use it here, and
> give it to drivers etc. Otherwise, drivers would have to take, e.g.
> 
>  - channel = 1 (2412 MHz)
>  - HT40+
> 
> and calculate
> 
>  - center freq = 2422 MHz
>  - bandwidth = 40
>  - control channel offset = 0
> 
> before being able to call this function. To me, that seems wrong.

I see, we could add helper function that will calculate
center_freq/bandwidth, but starting from defining new channel
structure and accompanying code in nl80211/mac80211 is more
reasonable.

Stanislaw