audio policy: fix gapless playback when effects enabled

Do not allow offloading if one non offloadable effect is enabled. This prevents from
creating an offloaded track and tearing it down immediately after start when audioflinger
detects there is an active non offloadable effect.
Not doing so breaks gapless playback because AwesomePlayer will always be able to open
an offloaded track which will not be compatible with the previous PCM track and
Audiosink::open() will not recycle it.

Bug: 11181933.
Change-Id: I6d163806849d9093b9ec701ba8e8c1ccb658e3c8

1 files changed, 40 insertions, 5 deletions

diff --git a/audio/AudioPolicyManagerBase.cpp b/audio/AudioPolicyManagerBase.cpp
index c176146..dbca8ff 100644
--- a/audio/AudioPolicyManagerBase.cpp
+++ b/audio/AudioPolicyManagerBase.cpp
@@ -582,11 +582,22 @@ audio_io_handle_t AudioPolicyManagerBase::getOutput(AudioSystem::stream_type str
         flags = (AudioSystem::output_flags)(flags | AUDIO_OUTPUT_FLAG_DIRECT);
     }
 
-    IOProfile *profile = getProfileForDirectOutput(device,
-                                                   samplingRate,
-                                                   format,
-                                                   channelMask,
-                                                   (audio_output_flags_t)flags);
+    // Do not allow offloading if one non offloadable effect is enabled. This prevents from
+    // creating an offloaded track and tearing it down immediately after start when audioflinger
+    // detects there is an active non offloadable effect.
+    // FIXME: We should check the audio session here but we do not have it in this context.
+    // This may prevent offloading in rare situations where effects are left active by apps
+    // in the background.
+    IOProfile *profile = NULL;
+    if (((flags & AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD) == 0) ||
+            !isNonOffloadableEffectEnabled()) {
+        profile = getProfileForDirectOutput(device,
+                                           samplingRate,
+                                           format,
+                                           channelMask,
+                                           (audio_output_flags_t)flags);
+    }
+
     if (profile != NULL) {
         AudioOutputDescriptor *outputDesc = NULL;
 
@@ -1299,6 +1310,20 @@ status_t AudioPolicyManagerBase::setEffectEnabled(EffectDescriptor *pDesc, bool
     return NO_ERROR;
 }
 
+bool AudioPolicyManagerBase::isNonOffloadableEffectEnabled()
+{
+    for (size_t i = 0; i < mEffects.size(); i++) {
+        const EffectDescriptor * const pDesc = mEffects.valueAt(i);
+        if (pDesc->mEnabled && (pDesc->mStrategy == STRATEGY_MEDIA) &&
+                ((pDesc->mDesc.flags & EFFECT_FLAG_OFFLOAD_SUPPORTED) == 0)) {
+            ALOGV("isNonOffloadableEffectEnabled() non offloadable effect %s enabled on session %d",
+                  pDesc->mDesc.name, pDesc->mSession);
+            return true;
+        }
+    }
+    return false;
+}
+
 bool AudioPolicyManagerBase::isStreamActive(int stream, uint32_t inPastMs) const
 {
     nsecs_t sysTime = systemTime();
@@ -1472,6 +1497,16 @@ bool AudioPolicyManagerBase::isOffloadSupported(const audio_offload_info_t& offl
         return false;
     }
 
+    // Do not allow offloading if one non offloadable effect is enabled. This prevents from
+    // creating an offloaded track and tearing it down immediately after start when audioflinger
+    // detects there is an active non offloadable effect.
+    // FIXME: We should check the audio session here but we do not have it in this context.
+    // This may prevent offloading in rare situations where effects are left active by apps
+    // in the background.
+    if (isNonOffloadableEffectEnabled()) {
+        return false;
+    }
+
     // See if there is a profile to support this.
     // AUDIO_DEVICE_NONE
     IOProfile *profile = getProfileForDirectOutput(AUDIO_DEVICE_NONE /*ignore device */,