3 files changed, 28 insertions, 4 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index 3261730181fa..77166520bc01 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -803,6 +803,27 @@ static void iwl_mvm_bss_info_changed_station(struct iwl_mvm *mvm,
                                 return;
                         }
                         iwl_mvm_configure_mcast_filter(mvm, vif);
+
+                        if (test_bit(IWL_MVM_STATUS_IN_HW_RESTART,
+                                     &mvm->status)) {
+                                /*
+                                 * If we're restarting then the firmware will
+                                 * obviously have lost synchronisation with
+                                 * the AP. It will attempt to synchronise by
+                                 * itself, but we can make it more reliable by
+                                 * scheduling a session protection time event.
+                                 *
+                                 * The firmware needs to receive a beacon to
+                                 * catch up with synchronisation, use 110% of
+                                 * the beacon interval.
+                                 *
+                                 * Set a large maximum delay to allow for more
+                                 * than a single interface.
+                                 */
+                                u32 dur = (11 * vif->bss_conf.beacon_int) / 10;
+                                iwl_mvm_protect_session(mvm, vif, dur, dur,
+                                                        5 * dur);
+                        }
                 } else if (mvmvif->ap_sta_id != IWL_MVM_STATION_COUNT) {
                         /* remove AP station now that the MAC is unassoc */
                         ret = iwl_mvm_rm_sta_id(mvm, vif, mvmvif->ap_sta_id);
@@ -1170,7 +1191,7 @@ static void iwl_mvm_mac_mgd_prepare_tx(struct ieee80211_hw *hw,
 
         mutex_lock(&mvm->mutex);
         /* Try really hard to protect the session and hear a beacon */
-        iwl_mvm_protect_session(mvm, vif, duration, min_duration);
+        iwl_mvm_protect_session(mvm, vif, duration, min_duration, 500);
         mutex_unlock(&mvm->mutex);
 }
 
diff --git a/drivers/net/wireless/iwlwifi/mvm/time-event.c b/drivers/net/wireless/iwlwifi/mvm/time-event.c
index 76a3c177e100..33cf56fdfc41 100644
--- a/drivers/net/wireless/iwlwifi/mvm/time-event.c
+++ b/drivers/net/wireless/iwlwifi/mvm/time-event.c
@@ -387,7 +387,8 @@ static int iwl_mvm_time_event_send_add(struct iwl_mvm *mvm,
 
 void iwl_mvm_protect_session(struct iwl_mvm *mvm,
                              struct ieee80211_vif *vif,
-                             u32 duration, u32 min_duration)
+                             u32 duration, u32 min_duration,
+                             u32 max_delay)
 {
         struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
         struct iwl_mvm_time_event_data *te_data = &mvmvif->time_event_data;
@@ -426,7 +427,7 @@ void iwl_mvm_protect_session(struct iwl_mvm *mvm,
                 cpu_to_le32(iwl_read_prph(mvm->trans, DEVICE_SYSTEM_TIME_REG));
 
         time_cmd.max_frags = TE_V2_FRAG_NONE;
-        time_cmd.max_delay = cpu_to_le32(500);
+        time_cmd.max_delay = cpu_to_le32(max_delay);
         /* TODO: why do we need to interval = bi if it is not periodic? */
         time_cmd.interval = cpu_to_le32(1);
         time_cmd.duration = cpu_to_le32(duration);
diff --git a/drivers/net/wireless/iwlwifi/mvm/time-event.h b/drivers/net/wireless/iwlwifi/mvm/time-event.h
index f86c51065ed3..d9c8d6cfa2db 100644
--- a/drivers/net/wireless/iwlwifi/mvm/time-event.h
+++ b/drivers/net/wireless/iwlwifi/mvm/time-event.h
@@ -123,6 +123,7 @@
  * @duration: the duration of the session in TU.
  * @min_duration: will start a new session if the current session will end
  *      in less than min_duration.
+ * @max_delay: maximum delay before starting the time event (in TU)
  *
  * This function can be used to start a session protection which means that the
  * fw will stay on the channel for %duration_ms milliseconds. This function
@@ -133,7 +134,8 @@
  */
 void iwl_mvm_protect_session(struct iwl_mvm *mvm,
                              struct ieee80211_vif *vif,
-                             u32 duration, u32 min_duration);
+                             u32 duration, u32 min_duration,
+                             u32 max_delay);
 
 /**
  * iwl_mvm_stop_session_protection - cancel the session protection.