@@ -932,7 +932,7 @@ static bool scan_use_rpa(struct hci_dev *hdev)
static void hci_req_start_scan(struct hci_request *req, u8 type, u16 interval,
u16 window, u8 own_addr_type, u8 filter_policy,
- bool addr_resolv)
+ bool filter_dup, bool addr_resolv)
{
struct hci_dev *hdev = req->hdev;
@@ -997,7 +997,7 @@ static void hci_req_start_scan(struct hci_request *req, u8 type, u16 interval,
memset(&ext_enable_cp, 0, sizeof(ext_enable_cp));
ext_enable_cp.enable = LE_SCAN_ENABLE;
- ext_enable_cp.filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
+ ext_enable_cp.filter_dup = filter_dup;
hci_req_add(req, HCI_OP_LE_SET_EXT_SCAN_ENABLE,
sizeof(ext_enable_cp), &ext_enable_cp);
@@ -1016,7 +1016,7 @@ static void hci_req_start_scan(struct hci_request *req, u8 type, u16 interval,
memset(&enable_cp, 0, sizeof(enable_cp));
enable_cp.enable = LE_SCAN_ENABLE;
- enable_cp.filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
+ enable_cp.filter_dup = filter_dup;
hci_req_add(req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(enable_cp),
&enable_cp);
}
@@ -1053,6 +1053,8 @@ void hci_req_add_le_passive_scan(struct hci_request *req)
u8 own_addr_type;
u8 filter_policy;
u16 window, interval;
+ /* Default is to enable duplicates filter */
+ u8 filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
/* Background scanning should run with address resolution */
bool addr_resolv = true;
@@ -1106,6 +1108,20 @@ void hci_req_add_le_passive_scan(struct hci_request *req)
} else if (hci_is_adv_monitoring(hdev)) {
window = hdev->le_scan_window_adv_monitor;
interval = hdev->le_scan_int_adv_monitor;
+
+ /* Disable duplicates filter when scanning for advertisement
+ * monitor for the following reasons.
+ *
+ * For HW pattern filtering (ex. MSFT), Realtek and Qualcomm
+ * controllers ignore RSSI_Sampling_Period when the duplicates
+ * filter is enabled.
+ *
+ * For SW pattern filtering, when we're not doing interleaved
+ * scanning, it is necessary to disable duplicates filter,
+ * otherwise hosts can only receive one advertisement and it's
+ * impossible to know if a peer is still in range.
+ */
+ filter_dup = LE_SCAN_FILTER_DUP_DISABLE;
} else {
window = hdev->le_scan_window;
interval = hdev->le_scan_interval;
@@ -1113,7 +1129,8 @@ void hci_req_add_le_passive_scan(struct hci_request *req)
bt_dev_dbg(hdev, "LE passive scan with whitelist = %d", filter_policy);
hci_req_start_scan(req, LE_SCAN_PASSIVE, interval, window,
- own_addr_type, filter_policy, addr_resolv);
+ own_addr_type, filter_policy, filter_dup,
+ addr_resolv);
}
static bool adv_instance_is_scannable(struct hci_dev *hdev, u8 instance)
@@ -3135,6 +3152,8 @@ static int active_scan(struct hci_request *req, unsigned long opt)
u8 own_addr_type;
/* White list is not used for discovery */
u8 filter_policy = 0x00;
+ /* Default is to enable duplicates filter */
+ u8 filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
/* Discovery doesn't require controller address resolution */
bool addr_resolv = false;
int err;
@@ -3159,9 +3178,26 @@ static int active_scan(struct hci_request *req, unsigned long opt)
if (err < 0)
own_addr_type = ADDR_LE_DEV_PUBLIC;
+ if (hci_is_adv_monitoring(hdev)) {
+ /* Duplicate filter should be disabled when some advertisement
+ * monitor is activated, otherwise AdvMon can only receive one
+ * advertisement for one peer(*) during active scanning, and
+ * might report loss to these peers.
+ *
+ * Note that different controllers have different meanings of
+ * |duplicate|. Some of them consider packets with the same
+ * address as duplicate, and others consider packets with the
+ * same address and the same RSSI as duplicate. Although in the
+ * latter case we don't need to disable duplicate filter, but
+ * it is common to have active scanning for a short period of
+ * time, the power impact should be neglectable.
+ */
+ filter_dup = LE_SCAN_FILTER_DUP_DISABLE;
+ }
+
hci_req_start_scan(req, LE_SCAN_ACTIVE, interval,
hdev->le_scan_window_discovery, own_addr_type,
- filter_policy, addr_resolv);
+ filter_policy, filter_dup, addr_resolv);
return 0;
}