@@ -331,6 +331,28 @@ ieee80211_determine_chantype(struct ieee80211_sub_if_data *sdata,
ret = 0;
out:
+ /*
+ * When tracking the current AP, don't do any further checks if the
+ * new chandef is identical to the one we're currently using for the
+ * connection. This keeps us from playing ping-pong with regulatory,
+ * without it the following can happen (for example):
+ * - connect to an AP with 80 MHz, world regdom allows 80 MHz
+ * - AP advertises regdom US
+ * - CRDA loads regdom US with 80 MHz prohibited (old database)
+ * - the code below detects an unsupported channel, downgrades, and
+ * we disconnect from the AP in the caller
+ * - disconnect causes CRDA to reload world regdomain and the game
+ * starts anew.
+ * (see https://bugzilla.kernel.org/show_bug.cgi?id=70881)
+ *
+ * It seems possible that there are still scenarios with CSA or real
+ * bandwidth changes where a this could happen, but those cases are
+ * less common and wouldn't completely prevent using the AP.
+ */
+ if (tracking &&
+ cfg80211_chandef_identical(chandef, &sdata->vif.bss_conf.chandef))
+ return ret;
+
/* don't print the message below for VHT mismatch if VHT is disabled */
if (ret & IEEE80211_STA_DISABLE_VHT)
vht_chandef = *chandef;