Pause Bluetooth discovery during active play

bluepad32_input_backend.cpp

@@ -85,6 +85,7 @@ enum class ConnectionStatus {
 enum class ConnectionPolicyState {
     Uninitialized,
     Open,
+    Passive,
     Paused,
     FailedClosed,
 };
@@ -624,26 +625,40 @@ void process_clear_pairings(uint32_t now_ms) {
 
 void apply_connection_policy() {
     const bool free_slot = has_free_slot();
-    if ((!free_slot &&
+    const bool active_controller = has_active_controller();
-         g_connection_policy_state == ConnectionPolicyState::Paused) ||
+    const bool pairing_open =
-        (free_slot &&
+        pairing_window_active_at(btstack_run_loop_get_time_ms());
-         g_connection_policy_state == ConnectionPolicyState::Open)) {
+    const bool active_scan =
+        free_slot && (!active_controller || pairing_open);
+    const ConnectionPolicyState desired_state =
+        !free_slot
+            ? ConnectionPolicyState::Paused
+            : (active_scan ? ConnectionPolicyState::Open
+                           : ConnectionPolicyState::Passive);
+    if (g_connection_policy_state == desired_state) {
         return;
     }
 
-    uni_bt_allow_incoming_connections(false);
+    // Classic inquiry and BLE scanning consume radio time and measurably delay
+    // active controller HID traffic. Stop them before every policy transition.
     uni_bt_stop_scanning_unsafe();
 
     if (!free_slot) {
+        uni_bt_allow_incoming_connections(false);
         g_connection_policy_state = ConnectionPolicyState::Paused;
         return;
     }
 
-    // Bluepad32's normal scan/autoconnect path handles both remembered
+    // Passive mode still accepts controller-initiated reconnects without
-    // controllers powering on and controllers in explicit pairing mode.
+    // running inquiry. Active discovery is reserved for zero-controller idle
+    // state and the explicit BOOTSEL pairing window.
     uni_bt_allow_incoming_connections(true);
-    uni_bt_start_scanning_and_autoconnect_unsafe();
+    if (active_scan) {
-    g_connection_policy_state = ConnectionPolicyState::Open;
+        uni_bt_start_scanning_and_autoconnect_unsafe();
+        g_connection_policy_state = ConnectionPolicyState::Open;
+    } else {
+        g_connection_policy_state = ConnectionPolicyState::Passive;
+    }
 }
 
 void update_status_led() {
@@ -676,7 +691,9 @@ void process_rumble_timer(btstack_timer_source_t* timer) {
     const uint32_t now_ms = btstack_run_loop_get_time_ms();
     process_clear_pairings(now_ms);
     process_pairing_snapshot_request();
-    update_pairing_window(now_ms);
+    if (update_pairing_window(now_ms)) {
+        apply_connection_policy();
+    }
 
     for (uint8_t slot_index = 0; slot_index < kSlotCount; ++slot_index) {
         RumbleEnvelope envelope{};
@@ -781,7 +798,8 @@ void platform_on_device_connected(uni_hid_device_t* device) {
     if (device == nullptr) {
         return;
     }
-    if (g_connection_policy_state != ConnectionPolicyState::Open) {
+    if (g_connection_policy_state != ConnectionPolicyState::Open &&
+        g_connection_policy_state != ConnectionPolicyState::Passive) {
         uni_hid_device_disconnect(device);
         return;
     }
@@ -833,9 +851,9 @@ void platform_on_device_disconnected(uni_hid_device_t* device) {
     critical_section_exit(&g_state_lock);
 
     if (disconnected_tracked_device) {
-        // A controller can disconnect while the policy is already Open.
+        // Re-evaluate from scratch: resume discovery only after the final
-        // Restart both scans so host-initiated reconnect controllers such as
+        // active controller disconnects; otherwise keep passive incoming
-        // 8BitDo Ultimate become reachable without rebooting the Pico.
+        // reconnect support without inquiry-induced latency.
         g_connection_policy_state = ConnectionPolicyState::Uninitialized;
         recompute_connection_status();
     }

tests/bluepad32_backend_lifecycle_test.cpp

@@ -800,13 +800,23 @@ void test_pairing_window_policy() {
                 g_connection_policy_state == ConnectionPolicyState::Paused,
             "Classic and BLE pairing authentication must close at the deadline");
     platform_on_device_disconnected(&devices[3]);
+    require(g_connection_policy_state == ConnectionPolicyState::Passive &&
+                !classic_scanning_enabled && !scanning_enabled &&
+                incoming_connections,
+            "a freed slot with active controllers must remain passive");
+    require(platform_on_device_discovered(address, "controller", 0, 0) ==
+                    UNI_ERROR_IGNORE_DEVICE,
+            "passive policy must reject inquiry discoveries");
+
+    bluepad32_input_backend_open_pairing_window();
+    process_rumble_timer(&g_rumble_timer);
     require(g_connection_policy_state == ConnectionPolicyState::Open &&
                 classic_scanning_enabled && scanning_enabled &&
                 incoming_connections,
-            "a freed slot must resume autoconnect after pairing indication expires");
+            "explicit BOOTSEL window must resume active discovery");
     require(platform_on_device_discovered(address, "controller", 0, 0) ==
                     UNI_ERROR_SUCCESS,
-            "resumed autoconnect must accept a discovered controller");
+            "pairing window discovery must accept a controller");
 }
 
 

tests/test_bluepad32_imu_normalization_native.py

@@ -19,6 +19,7 @@ def test_bluepad32_imu_normalization_native(tmp_path: Path) -> None:
             "-Wextra",
             "-Werror",
             "-pedantic",
+            f"-I{root / 'bluepad32_config'}",
             f"-I{root / 'external' / 'bluepad32' / 'src' / 'components' / 'bluepad32' / 'include'}",
             str(root / "tests" / "bluepad32_imu_normalization_test.cpp"),
             "-o",