Re: [RFC] wireless: improve dfs-region intersection.

[Ben Greear <greearb@candelatech.com>]

On 06/23/2014 12:15 PM, Luis R. Rodriguez wrote:
> 
> Adding wireless-regdb.
> 
> Regulatory folks:
> 
> if two cards are present on a system, in the worst case consider
> two different cards for AP mode, and one has a DFS region set for the
> country its on but the other does not, do we want to use the DFS region
> for both? DFS would not be allowed on system unless the DFS region is
> set. DFS operation requires a card to explicitly support DFS though so
> even though it can be set as an intersection each card would still
> require DFS suport for that region.
> 
> As I see it this will depend on what we want cards to do if the DFS
> region is unknown for a region. If the DFS region is not known can
> we use any DFS algorithm? If we cannot then I think a DFS intersection
> would require agreement on the DFS region. That would also mean though
> that when shipping products if a system is built with one card that has
> DFS for ETSI for example, and then a secondary card is present and its
> regulatory domain does not have DFS then the first card would not be
> able to operate on the DFS. I think this is reasonable given that 
> the two cards must at least agree on the regulatory domain, otherwise
> the folks doing system integration probably did a bad job at thinking
> of things ahead of time. Even though this can be technically true I
> foresee folks this misconfiguration happening in the future and folks
> beingp puzzled by this as an issue. This means this should be documented
> for folks selling devices in a combined wifi system.

Maybe some stuff should be per-NIC instead of per OS instance.  It would
suck if adding some ancient USB wifi NIC to a system disabled shiny new
features on already-existing NICs.

As for being confusing, the current code is nasty and it is very hard
to have any idea why things do or do not work, especially if you do not
have ability to add printk all over the place to figure out what the
code is actually doing.

I think some more effort should go into printing out a lot more
information about the regulator domain decisions, through printk
or related call if nothing better is found...

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com