On Tue, 2012-11-20 at 17:15 +0200, Victor Goldenshtein wrote: > On 14/11/2012 14:38, Johannes Berg wrote: > > On Wed, 2012-11-14 at 13:19 +0100, Michal Kazior wrote: > > > >>> However, then I realised that that still doesn't work -- once initial > >>> radar detection is done, it needs to continue while the AP is active. If > >>> the channel context was going to be relinquished, or even just the > >>> channel changed for a few seconds, it would be unsafe. So as a result, > >>> the radar detect operation has to somehow be coupled to the start AP > >>> operation and prohibit channel changes and additional channel contexts > >>> during the entire operation time. > >> > >> Hmm.. cfg80211 doesn't really know about channel contexts. > >> > >> The problem I see is that cfg80211 may be in a combination with > >> `num_different_channels = 1` and mac80211 can have 2 channel contexts > >> due to channel type incompatibilities. > > > > Yes, this is a concern, we need to fix that anyway though, otherwise it > > may assume that some operations are possible when they really aren't > > (e.g. starting an HT40+ and HT40- AP on the same channel, which > > shouldn't be done anyway, but still) > > > > not sure how it can happen if have this check: > > if ((cac_type != NL80211_CHAN_HT20) && (cac_type != NL80211_CHAN_NO_HT)) > return -EOPNOTSUPP; > > in both start_radar_detection() & enable_tx() ? The discussion between Michal and me above was unrelated to DFS :-) 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
