From bf7446cbcf1be81c6410fc02b2649ea1a12e2700 Mon Sep 17 00:00:00 2001
From: Marcel Holtmann <marcel@holtmann.org>
Date: Sat, 19 Jan 2013 23:18:45 -0800
Subject: [PATCH] core: Use delay between passive scanning iterations

Keeping the conroller active for passive scanning with the current
kernel interface seems inefficient since it automatically disables
the discovery procedure. So instead of restarting it right away,
introduce a small delay to give the controller more chances to sleep.
---
 src/adapter.c | 40 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/src/adapter.c b/src/adapter.c
index 5ba983fd9..1baf95723 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -84,6 +84,7 @@
 #define MODE_DISCOVERABLE	0x02
 #define MODE_UNKNOWN		0xff
 
+#define CONN_SCAN_TIMEOUT (3)
 #define IDLE_DISCOV_TIMEOUT (5)
 #define TEMP_DEV_TIMEOUT (3 * 60)
 
@@ -150,6 +151,7 @@ struct btd_adapter {
 	GSList *discovery_list;		/* list of discovery clients */
 	GSList *discovery_found;	/* list of found devices */
 	guint discovery_idle_timeout;	/* timeout between discovery runs */
+	guint passive_scan_timeout;	/* timeout between passive scans */
 	guint temp_devices_timeout;	/* timeout for temporary devices */
 
 	guint pairable_timeout_id;	/* pairable timeout id */
@@ -1103,15 +1105,34 @@ static void passive_scanning_complete(uint8_t status, uint16_t length,
 	}
 }
 
-static void trigger_passive_scanning(struct btd_adapter *adapter)
+static gboolean passive_scanning_timeout(gpointer user_data)
 {
+	struct btd_adapter *adapter = user_data;
 	struct mgmt_cp_start_discovery cp;
 
+	adapter->passive_scan_timeout = 0;
+
+	cp.type = (1 << BDADDR_LE_PUBLIC) | (1 << BDADDR_LE_RANDOM);
+
+	mgmt_send(adapter->mgmt, MGMT_OP_START_DISCOVERY,
+				adapter->dev_id, sizeof(cp), &cp,
+				passive_scanning_complete, adapter, NULL);
+
+	return FALSE;
+}
+
+static void trigger_passive_scanning(struct btd_adapter *adapter)
+{
 	if (!(adapter->current_settings & MGMT_SETTING_LE))
 		return;
 
 	DBG("");
 
+	if (adapter->passive_scan_timeout > 0) {
+		g_source_remove(adapter->passive_scan_timeout);
+		adapter->passive_scan_timeout = 0;
+	}
+
 	/*
 	 * If any client is running a discovery right now, then do not
 	 * even try to start passive scanning.
@@ -1139,11 +1160,16 @@ static void trigger_passive_scanning(struct btd_adapter *adapter)
 	if (!adapter->connect_list)
 		return;
 
-	cp.type = (1 << BDADDR_LE_PUBLIC) | (1 << BDADDR_LE_RANDOM);
+	adapter->passive_scan_timeout = g_timeout_add_seconds(CONN_SCAN_TIMEOUT,
+					passive_scanning_timeout, adapter);
+}
 
-	mgmt_send(adapter->mgmt, MGMT_OP_START_DISCOVERY,
-				adapter->dev_id, sizeof(cp), &cp,
-				passive_scanning_complete, adapter, NULL);
+static void cancel_passive_scanning(struct btd_adapter *adapter)
+{
+	if (adapter->passive_scan_timeout > 0) {
+		g_source_remove(adapter->passive_scan_timeout);
+		adapter->passive_scan_timeout = 0;
+	}
 }
 
 static void trigger_start_discovery(struct btd_adapter *adapter, guint delay);
@@ -1242,6 +1268,8 @@ static void trigger_start_discovery(struct btd_adapter *adapter, guint delay)
 
 	DBG("");
 
+	cancel_passive_scanning(adapter);
+
 	if (adapter->discovery_idle_timeout > 0) {
 		g_source_remove(adapter->discovery_idle_timeout);
 		adapter->discovery_idle_timeout = 0;
@@ -4074,6 +4102,8 @@ static void adapter_stop(struct btd_adapter *adapter)
 	/* check pending requests */
 	reply_pending_requests(adapter);
 
+	cancel_passive_scanning(adapter);
+
 	if (adapter->discovery_list) {
 		g_slist_free_full(adapter->discovery_list, discovery_free);
 		adapter->discovery_list = NULL;
-- 
2.47.3