On Tue, 2012-08-21 at 23:37 +0530, Mahesh Palivela wrote:

quoted

I think the question really is whether or not we actually need the
flags. Sometimes, but very rarely really, we need to answer the question

         Is this set of parameters allowed with the current regulatory
         rules?

There's nothing that says this needs to be a flag. It could just as well
be a function

bool regulatory_chan_use_permitted(...);

where the ... gives all the necessary parameters or maybe some structure
holding all these.

If this was a function, it could go back to the regulatory definitions
(that we hopefully keep track of in the kernel) and actually use the
algorithm that today we use to determine the flags to determine the
answer.

Today, with the flags, we basically pre-determine the answers to all
possible such questions, and encode the answers in the flags for each
channel. If we don't pre-determine the answers, then we can get away
without any flags at all.

Does that make sense?

Yes it does. Basically we want to retire look up table approach and 
compute everytime as its not scalable. Fine. In that case, even we need 
to cover HT20, HT40-, HT40+ as well right?

I think we should, yeah. Might even just start with that to make the
transition.

quoted

Still doesn't solve the problems we saw with how to configure the
channel with considerations such as
   - bandwidth
   - center frequency
   - primary subchannel
   - 80 + 80 (which is basically two such channels?)

Yes It does. From center freq, width, control chan offset we know the 
secondary chans. That's all we want. For 80+80 configuration, we will 
get two center freq values.

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.

johannes