From d00dd99229bc9ce78b0e8bb3bb523a3cd504473c Mon Sep 17 00:00:00 2001 From: Xiuzhuo Shang Date: Wed, 15 Jul 2026 17:06:35 +0800 Subject: [PATCH] adapter: restrict delta=0 RSSI to proximity filters When a discovery filter is active (filtered_discovery=true), BlueZ unconditionally calls device_set_rssi_with_delta(..., delta=0), causing every BLE advertisement to emit a PropertiesChanged(RSSI) signal regardless of whether the RSSI value changed. delta=0 is only needed when a client has expressed explicit proximity interest by setting an RSSI or pathloss threshold in its discovery filter. Filters that specify only transport type or UUIDs do not require per-packet RSSI precision; for those, the standard RSSI_THRESHOLD=8 rate-limiting is both correct and desirable. The problem is triggered on dual-mode adapters by a transport-only filter (e.g. Transport=le). In merge_discovery_filters(), the transport-specific scan type (SCAN_TYPE_LE=6) does not equal the adapter scan type (SCAN_TYPE_DUAL=7), so has_filtered_discovery is set, filtered_discovery becomes true, and delta=0 is applied even though no proximity condition was requested. With hundreds of BLE devices advertising simultaneously this generates hundreds of unnecessary PropertiesChanged(RSSI) signals per second. Confirmed on QCS6490 (BlueZ 5.72) with Transport=le filter: adapter.c: filtered_discovery=1 (current_discovery_filter=set) device.c: device_set_rssi_with_delta() rssi=-86 delta_threshold=0 device.c: device_set_rssi_with_delta() rssi=-79 delta_threshold=0 Add discovery_filter_has_proximity() which walks discovery_list and returns true only when at least one active filter carries a real proximity condition (rssi != DISTANCE_VAL_INVALID or pathloss != DISTANCE_VAL_INVALID). Use this to gate the delta=0 path. Other filter fields (transport, uuids, duplicate, discoverable) express capability or content criteria and carry no proximity implication, so they are intentionally excluded from the check. Upstream-Status: Backport [e004414a1751d29216ccab976d6c7174ec48d11c] Signed-off-by: Xiuzhuo Shang --- src/adapter.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/src/adapter.c b/src/adapter.c index fb95e8553..1023e43a2 100644 --- a/src/adapter.c +++ b/src/adapter.c @@ -7255,6 +7255,22 @@ static void filter_duplicate_data(void *data, void *user_data) *duplicate = client->discovery_filter->duplicate; } +static bool discovery_filter_has_proximity(struct btd_adapter *adapter) +{ + GSList *l; + + for (l = adapter->discovery_list; l; l = g_slist_next(l)) { + struct discovery_client *client = l->data; + struct discovery_filter *filter = client->discovery_filter; + + if (filter && (filter->rssi != DISTANCE_VAL_INVALID || + filter->pathloss != DISTANCE_VAL_INVALID)) + return true; + } + + return false; +} + static bool device_is_discoverable(struct btd_adapter *adapter, struct eir_data *eir, const char *addr, uint8_t bdaddr_type, bool *auto_connect) @@ -7451,7 +7467,8 @@ void btd_adapter_device_found(struct btd_adapter *adapter, if (name_resolve_failed) device_name_resolve_fail(dev); - if (adapter->filtered_discovery) + if (adapter->filtered_discovery && + discovery_filter_has_proximity(adapter)) device_set_rssi_with_delta(dev, rssi, 0); else device_set_rssi(dev, rssi); -- 2.43.0