[client/idd] audio: prevent recording transport stalls

Give microphone data priority over replaceable clock feedback and
reduce feedback traffic on the shared client-to-host FIFO.

Retry short FIFO stalls outside the realtime thread and coalesce
consecutive packets in the existing fixed Windows buffers.

Avoid one broker write per tiny PipeWire quantum without adding
allocations or intentional capture latency.

idd/LGIdd/audio/CLGAudioDevice.cpp

@@ -283,7 +283,7 @@ private:
   };
 
   mutable CSRWLock m_lock;
-  ILGAudioDeviceEvents * m_events = nullptr;
+  IAudioDeviceEvents * m_events = nullptr;
   HANDLE m_stopEvent    = nullptr;
   HANDLE m_wakeEvent    = nullptr;
   HANDLE m_controlEvent = nullptr;
@@ -340,7 +340,7 @@ private:
     return WaitForSingleObject(m_stopEvent, 0) == 0;
   }
 
-  void ClearPlaybackBlock()
+  void UnblockPlayback()
   {
     CSRWExclusiveLock lock(m_lock);
     m_playbackBlocked = false;
@@ -352,28 +352,28 @@ private:
     return m_playbackBlocked;
   }
 
-  void ClearClockFeedbackLocked()
+  void ClearFeedback()
   {
     m_clockFeedback = {};
     m_clockFeedbackPending = false;
   }
 
-  void ClearClockControlFailureLocked()
+  void ClearFaultLocked()
   {
     m_clockControlFailureActive = false;
     m_clockControlFailureSince = 0;
   }
 
-  void ResetClockControlLocked()
+  void ResetClockLocked()
   {
-    ClearClockFeedbackLocked();
-    ClearClockControlFailureLocked();
+    ClearFeedback();
+    ClearFaultLocked();
   }
 
-  void ResetClockControl()
+  void ResetClock()
   {
     CSRWExclusiveLock lock(m_lock);
-    ResetClockControlLocked();
+    ResetClockLocked();
   }
 
   static DWORD CALLBACK ThreadProc(void * opaque)
@@ -435,7 +435,7 @@ private:
 
   void Publish(AudioEndpointStatus next, bool advance)
   {
-    ILGAudioDeviceEvents * events = nullptr;
+    IAudioDeviceEvents * events = nullptr;
     {
       CSRWExclusiveLock lock(m_lock);
       if (advance)
@@ -447,7 +447,7 @@ private:
           next.active != m_status.active ||
           !SameStream(next.playback, m_status.playback))
       {
-        ResetClockControlLocked();
+        ResetClockLocked();
       }
       if (SameStatus(next, m_status))
         return;
@@ -458,7 +458,7 @@ private:
       events->LGAudioState(next);
   }
 
-  void PublishUnavailable(bool advance)
+  void PublishOffline(bool advance)
   {
     AudioEndpointStatus next;
     next.capabilities = 0;
@@ -477,7 +477,7 @@ private:
     return result;
   }
 
-  void PublishBrokerState(bool forceAdvance = false)
+  void PublishBroker(bool forceAdvance = false)
   {
     AudioEndpointStatus previous = Status();
     AudioEndpointStatus next;
@@ -519,7 +519,7 @@ private:
     if (previous.playback.generation != next.playback.generation ||
         previous.active != next.active || bindingChanged)
     {
-      ClearPlaybackBlock();
+      UnblockPlayback();
       m_renderSequenceValid = false;
       m_renderDiscontinuity = true;
     }
@@ -628,12 +628,12 @@ private:
     m_writeBytes   = 0;
     ResetEvent(m_writeOverlapped.hEvent);
     m_captureDiscontinuity = false;
-    ClearPlaybackBlock();
+    UnblockPlayback();
     m_renderSequenceValid = false;
     m_renderDiscontinuity = true;
   }
 
-  void ClearCaptureQueue()
+  void ClearCapture()
   {
     CSRWExclusiveLock lock(m_lock);
     m_captureHead  = 0;
@@ -642,7 +642,7 @@ private:
 
   void CloseBroker(bool publish = true)
   {
-    ResetClockControl();
+    ResetClock();
     if (m_handle == INVALID_HANDLE_VALUE)
       return;
 
@@ -668,14 +668,14 @@ private:
     m_captureStreamGeneration = 0;
     m_nextCaptureSequence = 0;
     m_captureDiscontinuity = false;
-    ClearCaptureQueue();
+    ClearCapture();
     if (!Stopping())
       m_nextOpenAt = GetTickCount64() + OPEN_RETRY_MS;
     if (publish || inactiveBarrier)
-      PublishUnavailable(true);
+      PublishOffline(true);
   }
 
-  bool FinishAbsentDeactivation()
+  bool FinishAbsentStop()
   {
     {
       CSRWExclusiveLock lock(m_lock);
@@ -683,11 +683,11 @@ private:
           m_activation != ActivationState::DEACTIVATING)
         return false;
       m_activation = ActivationState::IDLE;
-      ResetClockControlLocked();
+      ResetClockLocked();
       m_captureHead  = 0;
       m_captureCount = 0;
     }
-    PublishUnavailable(true);
+    PublishOffline(true);
     return true;
   }
 
@@ -724,7 +724,7 @@ private:
         DEBUG_WARN("Looking Glass Audio broker query failed: %lu", error);
       CloseBroker(false);
       m_nextOpenAt = now + OPEN_RETRY_MS;
-      PublishUnavailable(false);
+      PublishOffline(false);
       return false;
     }
 
@@ -738,7 +738,7 @@ private:
     }
     m_nextPollAt    = 0;
     DEBUG_INFO("Looking Glass Audio broker connected");
-    PublishBrokerState();
+    PublishBroker();
     return true;
   }
 
@@ -760,16 +760,16 @@ private:
     else if (!bound && m_activation == ActivationState::DEACTIVATING)
     {
       m_activation = ActivationState::IDLE;
-      ResetClockControlLocked();
+      ResetClockLocked();
       return true;
     }
     return false;
   }
 
-  void DropQueuedCapture()
+  void DropCapture()
   {
     bool ready = false;
-    ILGAudioDeviceEvents * events = nullptr;
+    IAudioDeviceEvents * events = nullptr;
     {
       CSRWExclusiveLock lock(m_lock);
       ready = m_captureCount == CAPTURE_SLOT_COUNT;
@@ -820,7 +820,7 @@ private:
     else if (!desired && initiallyBound)
     {
       CancelDataIo();
-      DropQueuedCapture();
+      DropCapture();
       if (!Unbind(error) && !Stopping())
         DEBUG_WARN("Looking Glass Audio broker unbind failed: %lu", error);
       if (!QueryState(error))
@@ -837,13 +837,13 @@ private:
         LGAUDIO_BROKER_STATE_DATA_PLANE_ACTIVE) != 0;
     const bool inactiveBarrier =
       FinishActivation(bound, dataPlaneActive);
-    PublishBrokerState(inactiveBarrier);
+    PublishBroker(inactiveBarrier);
     m_nextPollAt = now +
       (desired ? ACTIVE_POLL_MS : IDLE_POLL_MS);
     return true;
   }
 
-  void ProcessClockControl()
+  void ProcessClock()
   {
     AudioClockFeedback feedback;
     {
@@ -852,7 +852,7 @@ private:
         return;
 
       feedback = m_clockFeedback;
-      ClearClockFeedbackLocked();
+      ClearFeedback();
       if (!m_started || m_stopping ||
           m_activation != ActivationState::ACTIVE ||
           !(m_status.capabilities & AUDIO_CAP_CLOCK_FEEDBACK) ||
@@ -892,7 +892,7 @@ private:
         returned == 0)
     {
       CSRWExclusiveLock lock(m_lock);
-      ClearClockControlFailureLocked();
+      ClearFaultLocked();
       return;
     }
 
@@ -927,9 +927,9 @@ private:
     {
       CSRWExclusiveLock lock(m_lock);
       m_lastError = error;
-      ResetClockControlLocked();
+      ResetClockLocked();
     }
-    PublishBrokerState(true);
+    PublishBroker(true);
   }
 
   bool ValidateRender(const LGAudioBrokerPacketHeader& header,
@@ -1027,7 +1027,7 @@ private:
       if (m_renderDiscontinuity)
         packet.flags |= AUDIO_PACKET_DISCONTINUITY;
 
-      ILGAudioDeviceEvents * events = nullptr;
+      IAudioDeviceEvents * events = nullptr;
       uint64_t readySerial = 0;
       {
         CSRWSharedLock lock(m_lock);
@@ -1148,7 +1148,7 @@ private:
 
   bool PopCapture(CaptureSlot& result, bool& becameReady)
   {
-    ILGAudioDeviceEvents * events = nullptr;
+    IAudioDeviceEvents * events = nullptr;
     {
       CSRWExclusiveLock lock(m_lock);
       if (!m_captureCount)
@@ -1289,7 +1289,7 @@ private:
     while (!Stopping())
     {
       if (m_handle == INVALID_HANDLE_VALUE)
-        FinishAbsentDeactivation();
+        FinishAbsentStop();
       if (m_handle == INVALID_HANDLE_VALUE && !OpenBroker())
       {
         const HANDLE waits[] = { m_stopEvent, m_wakeEvent };
@@ -1310,7 +1310,7 @@ private:
 
       if (!Reconcile(false))
         continue;
-      ProcessClockControl();
+      ProcessClock();
       DeliverRender();
       StartWriteIo();
       StartRenderIo();
@@ -1328,7 +1328,7 @@ private:
     {
       CSRWExclusiveLock lock(m_lock);
       m_activation = ActivationState::DEACTIVATING;
-      ResetClockControlLocked();
+      ResetClockLocked();
     }
     if (m_handle != INVALID_HANDLE_VALUE)
     {
@@ -1340,7 +1340,7 @@ private:
       }
       CloseBroker(false);
     }
-    FinishAbsentDeactivation();
+    FinishAbsentStop();
     if (avTaskHandle)
       AvRevertMmThreadCharacteristics(avTaskHandle);
   }
@@ -1380,7 +1380,7 @@ public:
     Stop();
   }
 
-  bool Start(ILGAudioDeviceEvents& events)
+  bool Start(IAudioDeviceEvents& events)
   {
     CSRWExclusiveLock lock(m_lock);
     if (m_started)
@@ -1410,7 +1410,7 @@ public:
     m_events   = &events;
     m_started  = true;
     m_stopping = false;
-    ResetClockControlLocked();
+    ResetClockLocked();
     m_thread = CreateThread(nullptr, 0, ThreadProc, this, 0, nullptr);
     if (!m_thread)
     {
@@ -1430,7 +1430,7 @@ public:
       if (!m_started)
         return;
       m_stopping = true;
-      ResetClockControlLocked();
+      ResetClockLocked();
       thread = m_thread;
       SetEvent(m_stopEvent);
       SetEvent(m_wakeEvent);
@@ -1451,7 +1451,7 @@ public:
     m_captureCount = 0;
     m_activation   = ActivationState::IDLE;
     m_controlDirty = true;
-    ResetClockControlLocked();
+    ResetClockLocked();
     m_status = {};
     m_status.generation = m_endpointGeneration;
     CloseEvents();
@@ -1495,7 +1495,7 @@ public:
         return AudioResult::BUSY;
       if (m_activation == ActivationState::IDLE)
       {
-        ResetClockControlLocked();
+        ResetClockLocked();
         m_activation = ActivationState::ACTIVATING;
       }
     }
@@ -1503,7 +1503,7 @@ public:
              m_activation == ActivationState::ACTIVE)
     {
       m_activation = ActivationState::DEACTIVATING;
-      ResetClockControlLocked();
+      ResetClockLocked();
       m_controlDirty  = true;
       SetEvent(m_wakeEvent);
     }
@@ -1548,6 +1548,30 @@ public:
         m_status.capture.state != AudioStreamState::RUNNING ||
         !SameFormat(packet.format, m_status.capture.format))
       return AudioResult::UNAVAILABLE;
+
+    if (m_captureCount &&
+        !(packet.flags & AUDIO_PACKET_DISCONTINUITY))
+    {
+      CaptureSlot& tail = m_capture[
+        (m_captureHead + m_captureCount - 1) % CAPTURE_SLOT_COUNT];
+      if (tail.packet.endpointGeneration == packet.endpointGeneration &&
+          tail.packet.streamGeneration == packet.streamGeneration &&
+          SameFormat(tail.packet.format, packet.format) &&
+          packet.frames <=
+            AUDIO_MAX_FRAMES_PER_PACKET - tail.packet.frames &&
+          pcmBytes <= AUDIO_MAX_PCM_BYTES - tail.size)
+      {
+        if (silent)
+          memset(tail.data + tail.size, 0, pcmBytes);
+        else
+          memcpy(tail.data + tail.size, data, pcmBytes);
+        tail.packet.frames += packet.frames;
+        tail.size          += pcmBytes;
+        SetEvent(m_wakeEvent);
+        return AudioResult::ACCEPTED;
+      }
+    }
+
     if (m_captureCount == CAPTURE_SLOT_COUNT)
       return AudioResult::BUSY;
 
@@ -1595,7 +1619,7 @@ public:
     return AudioResult::ACCEPTED;
   }
 
-  void PlaybackReceiveReady()
+  void PlaybackReady()
   {
     bool wake = false;
     {
@@ -1622,7 +1646,7 @@ CLGAudioDevice::~CLGAudioDevice()
   Stop();
 }
 
-bool CLGAudioDevice::Start(ILGAudioDeviceEvents& events)
+bool CLGAudioDevice::Start(IAudioDeviceEvents& events)
 {
   return m_state && m_state->Start(events);
 }
@@ -1661,5 +1685,5 @@ AudioResult CLGAudioDevice::SetClockFeedback(
 void CLGAudioDevice::PlaybackReceiveReady()
 {
   if (m_state)
-    m_state->PlaybackReceiveReady();
+    m_state->PlaybackReady();
 }