Work around for HDMI audio output rediscovering transistion loss.

chromeos/audio/cras_audio_handler.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_
 #define CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_
 
 #include <stdint.h>
 #include <queue>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "base/timer/timer.h"
 #include "chromeos/audio/audio_device.h"
 #include "chromeos/audio/audio_pref_observer.h"
 #include "chromeos/dbus/audio_node.h"
 #include "chromeos/dbus/cras_audio_client.h"
 #include "chromeos/dbus/session_manager_client.h"
 #include "chromeos/dbus/volume_state.h"
 
 class PrefRegistrySimple;
 class PrefService;
 
@@ skipping 157 matching lines @@
 
   // Swaps the left and right channel of the internal speaker.
   // Swap the left and right channel if |swap| is true; otherwise, swap the left
   // and right channel back to the normal mode.
   // If the feature is not supported on the device, nothing happens.
   virtual void SwapInternalSpeakerLeftRightChannel(bool swap);
 
   // Enables error logging.
   virtual void LogErrors();
 
+  // If necessary, sets the starting point for re-discovering the active HDMI
+  // output device caused by device entering/exiting docking mode, HDMI display
+  // changing resolution, or chromeos device suspend/resume. If
+  // |force_rediscovering| is true, it will force to set the starting point for
+  // re-discovering the active HDMI output device again if it has been in the
+  // middle of rediscovering the HDMI active output device.
+  virtual void SetActiveHDMIOutoutRediscoveringIfNecessary(
+      bool force_rediscovering);
+
  protected:
   explicit CrasAudioHandler(
       scoped_refptr<AudioDevicesPrefHandler> audio_pref_handler);
   ~CrasAudioHandler() override;
 
  private:
   friend class CrasAudioHandlerTest;
 
   // CrasAudioClient::Observer overrides.
   void AudioClientRestarted() override;
@@ skipping 85 matching lines @@
   // primary active node. Otherwise, it will be added as an additional active
   // node.
   void AddActiveNode(uint64_t node_id, bool notify);
 
   // Adds |node_id| into additional active nodes.
   void AddAdditionalActiveNode(uint64_t node_id, bool notify);
 
   // Removes |node_id| from additional active nodes.
   void RemoveActiveNodeInternal(uint64_t node_id, bool notify);
 
+  void UpdateAudioAfterHDMIRediscoverGracePeriod();
+
+  bool IsHDMIPrimaryOutputDevice() const;
+
+  void StartHDMIRediscoverGracePeriod();
+
+  bool hdmi_rediscovering() const { return hdmi_rediscovering_; }
+
+  void SetHDMIRediscoverGracePeriodForTesting(int during_in_ms);

[cychiang, 2015/06/26 10:00:21]

should name it duration_in_ms  ?

[jennyz, 2015/06/29 20:49:41]

Done.

+
   enum DeviceStatus {
     OLD_DEVICE,
     NEW_DEVICE,
     CHANGED_DEVICE,
   };
 
   // Checks if |device| is a newly discovered, changed, or existing device for
   // the nodes sent from NodesChanged signal.
   DeviceStatus CheckDeviceStatus(const AudioDevice& device);
 
@@ skipping 15 matching lines @@
   uint64_t active_output_node_id_;
   uint64_t active_input_node_id_;
   bool has_alternative_input_;
   bool has_alternative_output_;
 
   bool output_mute_locked_;
 
   // Failures are not logged at startup, since CRAS may not be running yet.
   bool log_errors_;
 
+  // Timer for HDMI re-discovering grace period.
+  base::OneShotTimer<CrasAudioHandler> hdmi_rediscover_timer_;
+  int hdmi_rediscover_grace_period_duration_in_ms_;
+  bool hdmi_rediscovering_;
+
   base::WeakPtrFactory<CrasAudioHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CrasAudioHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_