[PATCH] hostapd: Don't force HT Mixed Mode for non-GF STAs

Helmut Schaa helmut.schaa
Wed Mar 2 01:17:38 PST 2011


Am Mittwoch, 2. M?rz 2011 schrieb Johannes Berg:
> On Wed, 2011-03-02 at 10:04 +0100, Helmut Schaa wrote:
> 
> > > Not sure really, this HT stuff isn't as well defined as we'd like :-)
> > 
> > Yes, but this particular part looks well enough defined to me ;)
> > 
> > 802.11n-2009, 9.13.3.1, page 143:
> > 
> > "When the HT Protection field is set to no protection mode or 20 MHz protection
> > mode and the Nongreenfield HT STAs Present field is set to 1, HT transmissions
> > that use the HT-greenfield format shall be protected."
> 
> Well, that's the external protocol between different stations. The
> internal protocol (API) between the components of each station is a
> different matter.

Right, nevertheless I think the AP should do the same as all associated STAs.
Everything else would be ... strange :)

> > So, in this case the driver used by the AP should also protect GF
> > transmissions as long as hostapd passes the new htopmode to it.
> 
> Maybe it should. I just don't think it does.

Yep, see my other mail.

However, since the same driver callback is used (at least for mac80211
drivers) for setting the ht_opmode in STA (from mac80211 mlme) and AP mode
(from hostapd), STA mode seems broken in some drivers as well.

Helmut



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