Add BLE lifecycle pause mechanism for memory mgmt

Introduces a global pause flag to temporarily block BLE stack auto-start during large memory allocations (e.g., in EPUB rendering). Also adds auto-restart logic for BLE scanning when device list is empty, and extensive debug logging for BLE scan lifecycle troubleshooting.

platformio.ini

@@ -94,6 +94,7 @@ build_flags =
   -DENABLE_SERIAL_LOG
   -DLOG_LEVEL=2 ; Set log level to debug for development builds
   -DFREEINK_CAP_BLE_HID_HOST=1 ; BLE HID page-turner host (NimBLE)
+  -DFREEINK_BLE_HID_SCAN_DEBUG=1 ; verbose BLE scan lifecycle/advertisement logs for bring-up
 
 
 [env:gh_release]

src/BleInput.cpp

@@ -12,6 +12,10 @@
 
 namespace bleinput {
 
+namespace {
+volatile bool g_lifecyclePaused = false;
+}
+
 // NimBLE controller init/deinit hang (interrupt WDT) if run at the 10 MHz low-power
 // frequency, so force normal CPU speed around both. Centralized here so every caller
 // (boot restore, settings toggle, reader toggle, sleep) is covered automatically.
@@ -28,6 +32,10 @@ void stop() {
   BleHid.end();
 }
 
+void setLifecyclePaused(bool paused) { g_lifecyclePaused = paused; }
+
+bool lifecyclePaused() { return g_lifecyclePaused; }
+
 bool encodeKey(const freeink::KeyEvent& ev, uint8_t& kind, uint8_t& value) {
   if (ev.special != freeink::SpecialKey::None) {
     kind = 0;

src/BleInput.h

@@ -32,6 +32,11 @@ bool ensureStarted();
 // Drop the active link (e.g. before deep sleep or when the user disables BT).
 void stop();
 
+// Temporarily block the main-loop BLE lifecycle from auto-starting the stack.
+// Used while a render path deliberately frees BLE RAM for a large allocation.
+void setLifecyclePaused(bool paused);
+bool lifecyclePaused();
+
 // Encode a decoded key event into the stable (kind, value) identity used by the
 // settings map. kind: 0 = SpecialKey, 1 = HID usage. Returns false when the event
 // carries no usable identity (no special key and no usage code).

src/activities/ActivityManager.cpp

@@ -254,6 +254,10 @@ bool ActivityManager::isReaderActivity() const {
          (currentActivity && currentActivity->isReaderActivity());
 }
 
+bool ActivityManager::currentKeepsBluetoothAlive() const {
+  return currentActivity && currentActivity->keepsBluetoothAlive();
+}
+
 void ActivityManager::requestGhostCleanup() {
   if (currentActivity) currentActivity->requestGhostCleanup();
 }

src/activities/ActivityManager.h

@@ -101,6 +101,7 @@ class ActivityManager {
 
   bool preventAutoSleep() const;
   bool isReaderActivity() const;
+  bool currentKeepsBluetoothAlive() const;
   // True if BLE should be resident for the current context: any reader (page-turner
   // input) or the Bluetooth settings screen (pairing) is on the stack.
   bool bluetoothShouldBeActive() const;

src/activities/reader/EpubReaderActivity.cpp

@@ -871,9 +871,11 @@ void EpubReaderActivity::render(RenderLock&& lock) {
         // Free the BLE stack, build, then restore it. The chapter is cached afterwards, so
         // this recovery runs at most once per uncached chapter; BT reconnects in a few s.
         LOG_INF("ERS", "Section build failed with Bluetooth on; freeing BLE RAM and retrying");
+        bleinput::setLifecyclePaused(true);
         bleinput::stop();
         built = buildSection();
         const bool bleOk = bleinput::ensureStarted();
+        bleinput::setLifecyclePaused(false);
         LOG_INF("ERS", "BLE restart after build: begin=%d", bleOk);
         // Hold the "BT Connecting..." popup until the remote re-links, then force the
         // page render below onto the ghost-cleanup (HALF) path so the popup clears

src/activities/settings/BluetoothSettingsActivity.cpp

@@ -2,6 +2,7 @@
 
 #include <BleKeyboardHost.h>
 #include <GfxRenderer.h>
+#include <Logging.h>
 
 #include <cstdio>
 
@@ -49,10 +50,15 @@ void BluetoothSettingsActivity::rebuildMenuRows() {
 }
 
 void BluetoothSettingsActivity::startScanView() {
+  LOG_INF("BLEUI", "scan view: begin running=%d scanning=%d devices=%u paired=%u", BleHid.isRunning(),
+          BleHid.isScanning(), BleHid.deviceCount(), BleHid.pairedCount());
   view = View::Scan;
   scanIndex = 0;
   awaitingConnect = false;
+  lastLoggedScanState = false;
+  lastLoggedDeviceCount = 0xFF;
   BleHid.startScan(kScanMs);
+  LOG_INF("BLEUI", "scan view: startScan requested scanning=%d devices=%u", BleHid.isScanning(), BleHid.deviceCount());
   requestUpdate();
 }
 
@@ -176,9 +182,18 @@ void BluetoothSettingsActivity::loop() {
     if (view == View::Menu) {
       handleMenuConfirm();
     } else if (view == View::Scan) {
-      if (!awaitingConnect && scanIndex < BleHid.deviceCount()) {
+      const int count = BleHid.deviceCount();
+      if (!awaitingConnect && count == 0 && !BleHid.isScanning()) {
+        LOG_INF("BLEUI", "scan view: restart scan requested");
+        BleHid.startScan(kScanMs);
+        LOG_INF("BLEUI", "scan view: restart scan state scanning=%d devices=%u", BleHid.isScanning(),
+                BleHid.deviceCount());
+        requestUpdate();
+      } else if (!awaitingConnect && scanIndex < count) {
         if (BleHid.isScanning()) BleHid.stopScan();
         const auto& d = BleHid.device(static_cast<uint8_t>(scanIndex));
+        LOG_INF("BLEUI", "scan view: connect addr=%s name='%s' rssi=%d type=%u hid=%d conn=%d", d.addr, d.name,
+                d.rssi, d.addrType, d.hid, d.connectable);
         awaitingConnect = true;
         setBanner(tr(STR_CONNECTING));
         BleHid.connect(d.addr);
@@ -189,7 +204,16 @@ void BluetoothSettingsActivity::loop() {
   }
 
   // The scan list changes as devices are discovered — keep repainting while active.
-  if (view == View::Scan && BleHid.isScanning()) requestUpdate();
+  if (view == View::Scan) {
+    const bool scanning = BleHid.isScanning();
+    const uint8_t deviceCount = BleHid.deviceCount();
+    if (scanning != lastLoggedScanState || deviceCount != lastLoggedDeviceCount) {
+      LOG_INF("BLEUI", "scan view: state scanning=%d devices=%u", scanning, deviceCount);
+      lastLoggedScanState = scanning;
+      lastLoggedDeviceCount = deviceCount;
+    }
+    if (scanning) requestUpdate();
+  }
 }
 
 std::string BluetoothSettingsActivity::deviceLabel(int index) const {
@@ -270,7 +294,8 @@ void BluetoothSettingsActivity::render(RenderLock&&) {
   }
 
   // Button hints differ by view (Menu selects; Scan and Paired both connect).
-  const char* confirm = view == View::Menu ? tr(STR_SELECT) : tr(STR_CONNECT);
+  const bool scanCanRestart = view == View::Scan && BleHid.deviceCount() == 0 && !BleHid.isScanning();
+  const char* confirm = view == View::Menu ? tr(STR_SELECT) : scanCanRestart ? "Scan" : tr(STR_CONNECT);
   const auto labels = mappedInput.mapLabels(tr(STR_BACK), confirm, tr(STR_DIR_UP), tr(STR_DIR_DOWN));
   GUI.drawButtonHints(renderer, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
 

src/activities/settings/BluetoothSettingsActivity.h

@@ -52,6 +52,8 @@ class BluetoothSettingsActivity final : public Activity {
   // Guards the Paired view's hold-to-forget so it fires once per hold and suppresses
   // the tap-to-connect on the same press.
   bool pairedActionTaken = false;
+  bool lastLoggedScanState = false;
+  uint8_t lastLoggedDeviceCount = 0xFF;
 
   void rebuildMenuRows();
   void handleMenuConfirm();

src/main.cpp

@@ -496,16 +496,34 @@ void setup() {
 void updateBluetoothLifecycle() {
   const bool wanted =
       SETTINGS.bluetoothEnabled && activityManager.bluetoothShouldBeActive() && WiFi.getMode() == WIFI_MODE_NULL;
+  if (wanted && !BleHid.isRunning() && bleinput::lifecyclePaused()) return;
   if (wanted && !BleHid.isRunning()) {
-    bleinput::ensureStarted();
-    // Single place BLE starts for normal use (reader entry, BT toggled on, etc.), so the
-    // "BT Connecting..." popup shows uniformly. Then clear it with a ghost-cleanup (HALF)
-    // refresh so a grayscale reader page doesn't ghost over the popup.
-    bleinput::showConnectingUntilLinked(renderer, mappedInputManager);
-    activityManager.requestGhostCleanup();
-    activityManager.requestUpdate();
+    LOG_INF("BLELC", "start requested enabled=%u reader=%d settings=%d wifi=%d paired=%u heap=%u maxAlloc=%u",
+            SETTINGS.bluetoothEnabled, activityManager.isReaderActivity(), activityManager.currentKeepsBluetoothAlive(),
+            WiFi.getMode(), BleHid.pairedCount(), ESP.getFreeHeap(), ESP.getMaxAllocHeap());
+    RenderLock renderLock;
+    if (!bleinput::ensureStarted()) {
+      LOG_ERR("BLELC", "start failed heap=%u maxAlloc=%u", ESP.getFreeHeap(), ESP.getMaxAllocHeap());
+      return;
+    }
+    LOG_INF("BLELC", "started paired=%u heap=%u maxAlloc=%u", BleHid.pairedCount(), ESP.getFreeHeap(),
+            ESP.getMaxAllocHeap());
+    HalPowerManager::Lock powerLock;
+    const bool showReconnectPopup =
+        activityManager.isReaderActivity() && !activityManager.currentKeepsBluetoothAlive() && BleHid.pairedCount() > 0;
+    if (showReconnectPopup) {
+      // Single place BLE starts for reader reconnect. Then clear it with a
+      // ghost-cleanup (HALF) refresh so a grayscale page doesn't ghost over the
+      // popup.
+      bleinput::showConnectingUntilLinked(renderer, mappedInputManager);
+      activityManager.requestGhostCleanup();
+      activityManager.requestUpdate();
+    }
   } else if (!wanted && BleHid.isRunning()) {
+    LOG_INF("BLELC", "stop requested enabled=%u active=%d wifi=%d heap=%u maxAlloc=%u", SETTINGS.bluetoothEnabled,
+            activityManager.bluetoothShouldBeActive(), WiFi.getMode(), ESP.getFreeHeap(), ESP.getMaxAllocHeap());
     bleinput::stop();
+    LOG_INF("BLELC", "stopped heap=%u maxAlloc=%u", ESP.getFreeHeap(), ESP.getMaxAllocHeap());
   }
 }