[PATCH 2/2] Don't post scan results when initial scan is emtpy

[Dan Nicholson]

When the initial scan is made, just the cached results from the driver
are used. If this is empty, it's useless to post the results since
another scan is being scheduled immediately. This just causes extra
processing from listeners for no gain.
---
 This really helps to avoid triggering a delay in NetworkManager. After
 the first ScanResultsAvailable has been received, it begins to back off
 actually fetching the results by 4 seconds. This is to avoid excessive
 fetching when background scans are being posted.

 wpa_supplicant/events.c |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index 0f9b338..04e3152 100644
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -551,9 +551,18 @@ static void wpa_supplicant_event_scan_results(struct wpa_supplicant *wpa_s)
 		goto req_scan;
 	}
 
-	wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_SCAN_RESULTS);
-
-	wpa_supplicant_dbus_notify_scan_results(wpa_s);
+	/*
+	 * Don't post the results if this was the initial cached
+	 * and there were no results.
+	 */
+	if (wpa_s->scan_res_tried == 1 && wpa_s->conf->ap_scan == 1 &&
+	    wpa_s->scan_res->num == 0) {
+		wpa_msg(wpa_s, MSG_DEBUG, "Cached scan results are "
+			"empty - not posting");
+	} else {
+		wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_SCAN_RESULTS);
+		wpa_supplicant_dbus_notify_scan_results(wpa_s);
+	}
 
 	if (wpa_s->conf->ap_scan == 2 || wpa_s->disconnected)
 		return;
-- 
1.5.5.1