iwlwifi: mvm: don't disconnect immediately if we don't hear beacons after CSA

When we switch channel, we may miss a few beacons on the
new channel. Don't disconnect if the time event for the
switch ends before we hear the beacons.

Note that this is relevant only for old devices that still
use the TIME_EVENT firmware API for channel switch.

The check that we hear a beacon before the time event
ends was meant to be used for the association time event
and not for the channel switch time event.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210411132130.3d710091a0bd.I37a161ffdfb099a10080fbdc3b70a4deb76952e2@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/time-event.c

 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
- * Copyright (C) 2012-2014, 2018-2020 Intel Corporation
+ * Copyright (C) 2012-2014, 2018-2021 Intel Corporation
  * Copyright (C) 2013-2015 Intel Mobile Communications GmbH
  * Copyright (C) 2017 Intel Deutschland GmbH
  */
@@ -294,6 +294,17 @@ static void iwl_mvm_te_handle_notif(struct iwl_mvm *mvm,
 			iwl_mvm_roc_finished(mvm);
 			break;
 		case NL80211_IFTYPE_STATION:
+			/*
+			 * If we are switching channel, don't disconnect
+			 * if the time event is already done. Beacons can
+			 * be delayed a bit after the switch.
+			 */
+			if (te_data->id == TE_CHANNEL_SWITCH_PERIOD) {
+				IWL_DEBUG_TE(mvm,
+					     "No beacon heard and the CS time event is over, don't disconnect\n");
+				break;
+			}
+
 			/*
 			 * By now, we should have finished association
 			 * and know the dtim period.