Hi Jouni, On Sat, Feb 7, 2015 at 1:57 PM, Jouni Malinen <j@xxxxx> wrote: > On Wed, Jan 07, 2015 at 05:50:11PM +0200, Eliad Peller wrote: >> Radar detection can last indefinite time. There is no >> point in deferring a scan request in this case - simply >> return -EBUSY. > >> diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c >> @@ -505,7 +505,7 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, >> - if (local->scan_req) >> + if (local->scan_req || ieee80211_is_radar_required(local)) >> return -EBUSY; > > This seems to be breaking a hwsim test case sequence of ap_vht80plus80 > followed by ap_vht80. In such a case, all the HT40 scans for ap_vht80 > fail due to this added condition resulting in -EBUSY being returned > every time. It looks like this happens even if I change ap_vht80 to use > the same country code (US) as ap_vht80plus80, so the change in the > country code does not explain this either. > > I'm not sure what is causing the issue here, but it looks like something > in ap_vht80plus80 (i.e., an attempt to enable a channel combination that > would require DFS on one of the 80 MHz segments) leaves behind state > that makes ieee80211_is_radar_required(local) return true even when it > shouldn't. DFS for 80+80 is not yet supported, so I'd assume this is > somehow related to that. Anyway, I don't think mac80211 should behave in > this way. > Thanks for the detailed report. There was indeed stale state. I've just sent a patch to fix it. I don't see why returning EBUSY is wrong, though. Actually, it just make the test fail immediately, instead of waiting indefinitely until a timeout occurs (i guess, didn't actually test it with the reverted patch). This was exactly the intended behavior, and i think it makes much more sense. Eliad. -- 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
