On Mon, 2012-03-19 at 09:19 +0530, Sujith Manoharan wrote: > Adrian Chadd wrote: > > On 18 March 2012 03:19, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > > > > > I'm not sure I can believe this -- surely the firmware has to have a way > > > of dealing with stations that can't do 40 MHz and stations that can, so > > > switching between the two doesn't seem like a major proposal? We also > > > don't currently handle the action frames for that, but it seems like we > > > should. > > > > > > Note, however, that we're now discussing something already done -- > > > Paul's patch already removed the channel type update when all we wanted > > > was update the RC. > > > > When are stations being notified of a CWM change? > > > > I know FreeBSD handles it with a big stick at the moment - it just > > does a full interface reset and channel change. I don't necessarily > > like it, but I haven't yet sat down to look at when and why this is > > occuring. > > For AP mode, we currently don't have dynamic CWM - and if it is ever implemented, > it would probably be in hostapd. Yeah, though I think if we implement the action frame in mac80211 we could handle that in AP mode too? Might be easier not to though. > For station mode, HT bandwidth changes can be notified via beacons, probe responses > or action frames. mac80211 currently processes beacons and the HT operation element. > > Also, only legacy CSA announcements are handled by mac80211 right now, the 11n > extensions to the CSA action frame are yet to be implemented. Yeah, at least for VHT I'd guess those will become necessary. > As far as ath9k/ath9k_htc is concerned, I think we have to reset/reconfigure the HW > when a channel switch happens, since we reprogram various MAC/PHY registers based on > the HT bandwidth. Both ath9k and ath9k_htc update their rate control modules > correctly - ath9k via the rate_update() callback and ath9k_htc using BSS_CHANGED_HT > in bss_info_changed(). I'm not sure ath9k_htc is behaving correctly. Ok I should say that differently -- it's probably behaving "correctly" wrt. whatever mac80211 did before, but we're changing the way mac80211 behaves and I believe that to be (more) correct, see my other email. johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
