AudioTrack and AudioFlinger send level cleanup
Add an API to control block for getting/setting send level.
This allow us to make the mSendLevel field private.
Document the lack of barriers.
Use 0.0f to initialize floating-point values (for doc only).
Change-Id: I59f83b00adeb89eeee227e7648625d9a835be7a4
diff --git a/include/private/media/AudioTrackShared.h b/include/private/media/AudioTrackShared.h
index 046d5e9..86e0682 100644
--- a/include/private/media/AudioTrackShared.h
+++ b/include/private/media/AudioTrackShared.h
@@ -85,7 +85,9 @@
uint16_t bufferTimeoutMs; // Maximum cumulated timeout before restarting audioflinger
uint16_t waitTimeMs; // Cumulated wait time
- uint16_t sendLevel;
+private:
+ uint16_t mSendLevel; // Fixed point U4.12 so 0x1000 means 1.0
+public:
volatile int32_t flags;
// Cache line boundary (32 bytes)
@@ -98,6 +100,19 @@
uint32_t framesAvailable_l();
uint32_t framesReady();
bool tryLock();
+
+ // No barriers on the following operations, so the ordering of loads/stores
+ // with respect to other parameters is UNPREDICTABLE. That's considered safe.
+
+ // for AudioTrack client only, caller must limit to 0.0 <= sendLevel <= 1.0
+ void setSendLevel(float sendLevel) {
+ mSendLevel = uint16_t(sendLevel * 0x1000);
+ }
+
+ // for AudioFlinger only; the return value must be validated by the caller
+ uint16_t getSendLevel_U4_12() const {
+ return mSendLevel;
+ }
};
diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index 9c650ad..3a938dd 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -215,7 +215,7 @@
mVolume[LEFT] = 1.0f;
mVolume[RIGHT] = 1.0f;
- mSendLevel = 0;
+ mSendLevel = 0.0f;
mFrameCount = frameCount;
mNotificationFramesReq = notificationFrames;
mSessionId = sessionId;
@@ -499,14 +499,14 @@
status_t AudioTrack::setAuxEffectSendLevel(float level)
{
ALOGV("setAuxEffectSendLevel(%f)", level);
- if (level > 1.0f) {
+ if (level < 0.0f || level > 1.0f) {
return BAD_VALUE;
}
AutoMutex lock(mLock);
mSendLevel = level;
- mCblk->sendLevel = uint16_t(level * 0x1000);
+ mCblk->setSendLevel(level);
return NO_ERROR;
}
@@ -818,7 +818,7 @@
}
mCblk->volumeLR = (uint32_t(uint16_t(mVolume[RIGHT] * 0x1000)) << 16) | uint16_t(mVolume[LEFT] * 0x1000);
- mCblk->sendLevel = uint16_t(mSendLevel * 0x1000);
+ mCblk->setSendLevel(mSendLevel);
mAudioTrack->attachAuxEffect(mAuxEffectId);
mCblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
mCblk->waitTimeMs = 0;
@@ -1311,7 +1311,7 @@
: lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
userBase(0), serverBase(0), buffers(0), frameCount(0),
loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), volumeLR(0),
- sendLevel(0), flags(0)
+ mSendLevel(0), flags(0)
{
}
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 9fb666e..7f43100 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -2183,7 +2183,13 @@
vl = (uint32_t)(v * cblk->volume[0]) << 12;
vr = (uint32_t)(v * cblk->volume[1]) << 12;
- va = (uint32_t)(v * cblk->sendLevel);
+ uint16_t sendLevel = cblk->getSendLevel_U4_12();
+ // send level comes from shared memory and so may be corrupt
+ if (sendLevel >= 0x1000) {
+ ALOGV("Track send level out of range: %04X", sendLevel);
+ sendLevel = 0x1000;
+ }
+ va = (uint32_t)(v * sendLevel);
}
// Delegate volume control to effect in track effect chain if needed
if (chain != 0 && chain->setVolume_l(&vl, &vr)) {
