diff --git a/src/ap/drv_callbacks.c b/src/ap/drv_callbacks.c
index 8ddf754f6..58753e55a 100644
--- a/src/ap/drv_callbacks.c
+++ b/src/ap/drv_callbacks.c
@@ -772,7 +772,8 @@ void hostapd_event_sta_opmode_changed(struct hostapd_data *hapd, const u8 *addr,
 
 
 void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
-			     int offset, int width, int cf1, int cf2)
+			     int offset, int width, int cf1, int cf2,
+			     int finished)
 {
 	/* TODO: If OCV is enabled deauth STAs that don't perform a SA Query */
 
@@ -783,7 +784,8 @@ void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
 
 	hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
 		       HOSTAPD_LEVEL_INFO,
-		       "driver had channel switch: freq=%d, ht=%d, vht_ch=0x%x, offset=%d, width=%d (%s), cf1=%d, cf2=%d",
+		       "driver %s channel switch: freq=%d, ht=%d, vht_ch=0x%x, offset=%d, width=%d (%s), cf1=%d, cf2=%d",
+		       finished ? "had" : "starting",
 		       freq, ht, hapd->iconf->ch_switch_vht_config, offset,
 		       width, channel_width_to_string(width), cf1, cf2);
 
@@ -851,6 +853,15 @@ void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
 	is_dfs = ieee80211_is_dfs(freq, hapd->iface->hw_features,
 				  hapd->iface->num_hw_features);
 
+	wpa_msg(hapd->msg_ctx, MSG_INFO,
+		"%sfreq=%d ht_enabled=%d ch_offset=%d ch_width=%s cf1=%d cf2=%d dfs=%d",
+		finished ? WPA_EVENT_CHANNEL_SWITCH :
+		WPA_EVENT_CHANNEL_SWITCH_STARTED,
+		freq, ht, offset, channel_width_to_string(width),
+		cf1, cf2, is_dfs);
+	if (!finished)
+		return;
+
 	if (hapd->csa_in_progress &&
 	    freq == hapd->cs_freq_params.freq) {
 		hostapd_cleanup_cs_params(hapd);
@@ -1689,6 +1700,7 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 	case EVENT_AUTH:
 		hostapd_notif_auth(hapd, &data->auth);
 		break;
+	case EVENT_CH_SWITCH_STARTED:
 	case EVENT_CH_SWITCH:
 		if (!data)
 			break;
@@ -1697,7 +1709,8 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 					data->ch_switch.ch_offset,
 					data->ch_switch.ch_width,
 					data->ch_switch.cf1,
-					data->ch_switch.cf2);
+					data->ch_switch.cf2,
+					event == EVENT_CH_SWITCH);
 		break;
 	case EVENT_CONNECT_FAILED_REASON:
 		if (!data)
diff --git a/src/ap/hostapd.h b/src/ap/hostapd.h
index 790d37754..0f76cd6c8 100644
--- a/src/ap/hostapd.h
+++ b/src/ap/hostapd.h
@@ -607,7 +607,8 @@ int hostapd_probe_req_rx(struct hostapd_data *hapd, const u8 *sa, const u8 *da,
 			 const u8 *bssid, const u8 *ie, size_t ie_len,
 			 int ssi_signal);
 void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
-			     int offset, int width, int cf1, int cf2);
+			     int offset, int width, int cf1, int cf2,
+			     int finished);
 struct survey_results;
 void hostapd_event_get_survey(struct hostapd_iface *iface,
 			      struct survey_results *survey_results);
diff --git a/src/common/wpa_ctrl.h b/src/common/wpa_ctrl.h
index f65077e04..b24ae63e5 100644
--- a/src/common/wpa_ctrl.h
+++ b/src/common/wpa_ctrl.h
@@ -87,6 +87,9 @@ extern "C" {
 #define WPA_EVENT_BEACON_LOSS "CTRL-EVENT-BEACON-LOSS "
 /** Regulatory domain channel */
 #define WPA_EVENT_REGDOM_CHANGE "CTRL-EVENT-REGDOM-CHANGE "
+/** Channel switch started (followed by freq=<MHz> and other channel parameters)
+ */
+#define WPA_EVENT_CHANNEL_SWITCH_STARTED "CTRL-EVENT-STARTED-CHANNEL-SWITCH "
 /** Channel switch (followed by freq=<MHz> and other channel parameters) */
 #define WPA_EVENT_CHANNEL_SWITCH "CTRL-EVENT-CHANNEL-SWITCH "
 /** SAE authentication failed due to unknown password identifier */
diff --git a/src/drivers/driver.h b/src/drivers/driver.h
index cb561acba..095bfd96a 100644
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -1122,6 +1122,11 @@ enum hide_ssid {
 	HIDDEN_SSID_ZERO_CONTENTS
 };
 
+enum ch_switch_state {
+	CH_SW_STARTED,
+	CH_SW_FINISHED
+};
+
 struct wowlan_triggers {
 	u8 any;
 	u8 disconnect;
@@ -4540,6 +4545,15 @@ enum wpa_event_type {
 	 * */
 	EVENT_CH_SWITCH,
 
+	/**
+	 * EVENT_CH_SWITCH_STARTED - AP or GO started to switch channels
+	 *
+	 * This is a pre-switch event indicating the shortly following switch
+	 * of operating channels.
+	 *
+	 * Described in wpa_event_data.ch_switch
+	 */
+	EVENT_CH_SWITCH_STARTED,
 	/**
 	 * EVENT_WNM - Request WNM operation
 	 *
diff --git a/src/drivers/driver_common.c b/src/drivers/driver_common.c
index e55e6cd2b..b52e8baba 100644
--- a/src/drivers/driver_common.c
+++ b/src/drivers/driver_common.c
@@ -67,6 +67,7 @@ const char * event_to_string(enum wpa_event_type event)
 	E2S(DRIVER_CLIENT_POLL_OK);
 	E2S(EAPOL_TX_STATUS);
 	E2S(CH_SWITCH);
+	E2S(CH_SWITCH_STARTED);
 	E2S(WNM);
 	E2S(CONNECT_FAILED_REASON);
 	E2S(DFS_RADAR_DETECTED);
diff --git a/src/drivers/driver_nl80211_event.c b/src/drivers/driver_nl80211_event.c
index ee7b4da38..7abbafcd8 100644
--- a/src/drivers/driver_nl80211_event.c
+++ b/src/drivers/driver_nl80211_event.c
@@ -534,7 +534,8 @@ static int calculate_chan_offset(int width, int freq, int cf1, int cf2)
 static void mlme_event_ch_switch(struct wpa_driver_nl80211_data *drv,
 				 struct nlattr *ifindex, struct nlattr *freq,
 				 struct nlattr *type, struct nlattr *bw,
-				 struct nlattr *cf1, struct nlattr *cf2)
+				 struct nlattr *cf1, struct nlattr *cf2,
+				 int finished)
 {
 	struct i802_bss *bss;
 	union wpa_event_data data;
@@ -542,7 +543,8 @@ static void mlme_event_ch_switch(struct wpa_driver_nl80211_data *drv,
 	int chan_offset = 0;
 	int ifidx;
 
-	wpa_printf(MSG_DEBUG, "nl80211: Channel switch event");
+	wpa_printf(MSG_DEBUG, "nl80211: Channel switch%s event",
+		   finished ? "" : " started");
 
 	if (!freq)
 		return;
@@ -596,7 +598,8 @@ static void mlme_event_ch_switch(struct wpa_driver_nl80211_data *drv,
 	bss->freq = data.ch_switch.freq;
 	drv->assoc_freq = data.ch_switch.freq;
 
-	wpa_supplicant_event(bss->ctx, EVENT_CH_SWITCH, &data);
+	wpa_supplicant_event(bss->ctx, finished ?
+			     EVENT_CH_SWITCH : EVENT_CH_SWITCH_STARTED, &data);
 }
 
 
@@ -2508,6 +2511,16 @@ static void do_process_drv_event(struct i802_bss *bss, int cmd,
 				   tb[NL80211_ATTR_PMK],
 				   tb[NL80211_ATTR_PMKID]);
 		break;
+	case NL80211_CMD_CH_SWITCH_STARTED_NOTIFY:
+		mlme_event_ch_switch(drv,
+				     tb[NL80211_ATTR_IFINDEX],
+				     tb[NL80211_ATTR_WIPHY_FREQ],
+				     tb[NL80211_ATTR_WIPHY_CHANNEL_TYPE],
+				     tb[NL80211_ATTR_CHANNEL_WIDTH],
+				     tb[NL80211_ATTR_CENTER_FREQ1],
+				     tb[NL80211_ATTR_CENTER_FREQ2],
+				     0);
+		break;
 	case NL80211_CMD_CH_SWITCH_NOTIFY:
 		mlme_event_ch_switch(drv,
 				     tb[NL80211_ATTR_IFINDEX],
@@ -2515,7 +2528,8 @@ static void do_process_drv_event(struct i802_bss *bss, int cmd,
 				     tb[NL80211_ATTR_WIPHY_CHANNEL_TYPE],
 				     tb[NL80211_ATTR_CHANNEL_WIDTH],
 				     tb[NL80211_ATTR_CENTER_FREQ1],
-				     tb[NL80211_ATTR_CENTER_FREQ2]);
+				     tb[NL80211_ATTR_CENTER_FREQ2],
+				     1);
 		break;
 	case NL80211_CMD_DISCONNECT:
 		mlme_event_disconnect(drv, tb[NL80211_ATTR_REASON_CODE],
diff --git a/wpa_supplicant/ap.c b/wpa_supplicant/ap.c
index 4e1916942..7a3ec3067 100644
--- a/wpa_supplicant/ap.c
+++ b/wpa_supplicant/ap.c
@@ -1387,7 +1387,7 @@ int ap_ctrl_iface_chanswitch(struct wpa_supplicant *wpa_s, const char *pos)
 
 
 void wpas_ap_ch_switch(struct wpa_supplicant *wpa_s, int freq, int ht,
-		       int offset, int width, int cf1, int cf2)
+		       int offset, int width, int cf1, int cf2, int finished)
 {
 	struct hostapd_iface *iface = wpa_s->ap_iface;
 
@@ -1399,7 +1399,7 @@ void wpas_ap_ch_switch(struct wpa_supplicant *wpa_s, int freq, int ht,
 	if (wpa_s->current_ssid)
 		wpa_s->current_ssid->frequency = freq;
 	hostapd_event_ch_switch(iface->bss[0], freq, ht,
-				offset, width, cf1, cf2);
+				offset, width, cf1, cf2, finished);
 }
 
 
diff --git a/wpa_supplicant/ap.h b/wpa_supplicant/ap.h
index 447b55186..6c6e94cdf 100644
--- a/wpa_supplicant/ap.h
+++ b/wpa_supplicant/ap.h
@@ -54,7 +54,7 @@ int ap_switch_channel(struct wpa_supplicant *wpa_s,
 		      struct csa_settings *settings);
 int ap_ctrl_iface_chanswitch(struct wpa_supplicant *wpa_s, const char *txtaddr);
 void wpas_ap_ch_switch(struct wpa_supplicant *wpa_s, int freq, int ht,
-		       int offset, int width, int cf1, int cf2);
+		       int offset, int width, int cf1, int cf2, int finished);
 struct wpabuf * wpas_ap_wps_nfc_config_token(struct wpa_supplicant *wpa_s,
 					     int ndef);
 #ifdef CONFIG_AP
diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index 3ff8ba92d..cab0a6d9a 100644
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -4462,18 +4462,24 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 				       data->rx_from_unknown.wds);
 		break;
 #endif /* CONFIG_AP */
+
+	case EVENT_CH_SWITCH_STARTED:
 	case EVENT_CH_SWITCH:
 		if (!data || !wpa_s->current_ssid)
 			break;
 
-		wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_CHANNEL_SWITCH
-			"freq=%d ht_enabled=%d ch_offset=%d ch_width=%s cf1=%d cf2=%d",
+		wpa_msg(wpa_s, MSG_INFO,
+			"%sfreq=%d ht_enabled=%d ch_offset=%d ch_width=%s cf1=%d cf2=%d",
+			event == EVENT_CH_SWITCH ? WPA_EVENT_CHANNEL_SWITCH :
+			WPA_EVENT_CHANNEL_SWITCH_STARTED,
 			data->ch_switch.freq,
 			data->ch_switch.ht_enabled,
 			data->ch_switch.ch_offset,
 			channel_width_to_string(data->ch_switch.ch_width),
 			data->ch_switch.cf1,
 			data->ch_switch.cf2);
+		if (event == EVENT_CH_SWITCH_STARTED)
+			break;
 
 		wpa_s->assoc_freq = data->ch_switch.freq;
 		wpa_s->current_ssid->frequency = data->ch_switch.freq;
@@ -4489,7 +4495,8 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 					  data->ch_switch.ch_offset,
 					  data->ch_switch.ch_width,
 					  data->ch_switch.cf1,
-					  data->ch_switch.cf2);
+					  data->ch_switch.cf2,
+					  1);
 		}
 #endif /* CONFIG_AP */