On Fri, 2017-09-08 at 10:43 +0200, Richard Schütz wrote:

quoted

Hmm, I guess technically you're correct, since 11b added what's now
Clause 16 (was Clause 18 at the time), and that has all of them
mandatory? But perhaps this was actually intended for Clause 15
compatibility?

Compatibility in what way?

Well, realistically there are only three users of this information:

 * ieee80211_mandatory_rates(), used for supported station rates if we
   don't know anything better in IBSS (and OCB) and for basic rates in
   mesh;
 * basic rates in IBSS (__cfg80211_join_ibss);
 * duration calculation in ieee80211_duration, but that's just a
   fallback

So I guess it's now pretty unlikely that anyone would have a pre-11b
device, so it would make sense to actually make this change.

johannes