Merge "Pause faster during audio underrun" (daa3ff8b) · Commits · e / os / android_frameworks_av

services/audioflinger/Threads.cpp

+34 −11

Original line number	Diff line number	Diff line
		@@ -178,6 +178,11 @@ static const nsecs_t kOffloadStandbyDelayNs = seconds(1);
		// Direct output thread minimum sleep time in idle or active(underrun) state
		static const nsecs_t kDirectMinSleepTimeUs = 10000;

		// Minimum amount of time between checking to see if the timestamp is advancing
		// for underrun detection. If we check too frequently, we may not detect a
		// timestamp update and will falsely detect underrun.
		static const nsecs_t kMinimumTimeBetweenTimestampChecksNs = 150 /* ms / 1000;

		// The universal constant for ubiquitous 20ms value. The value of 20ms seems to provide a good
		// balance between power consumption and latency, and allows threads to be scheduled reliably
		// by the CFS scheduler.
		@@ -2040,7 +2045,8 @@ AudioFlinger::PlaybackThread::PlaybackThread(const sp<AudioFlinger>& audioFlinge
		mFastTrackAvailMask(((1 << FastMixerState::sMaxFastTracks) - 1) & ~1),
		mHwSupportsPause(false), mHwPaused(false), mFlushPending(false),
		mLeftVolFloat(-1.0), mRightVolFloat(-1.0),
		mDownStreamPatch{}
		mDownStreamPatch{},
		mIsTimestampAdvancing(kMinimumTimeBetweenTimestampChecksNs)
		{
		snprintf(mThreadName, kThreadNameLength, "AudioOut_%X", id);
		mNBLogWriter = audioFlinger->newWriter_l(kLogSize, mThreadName);
		@@ -5902,18 +5908,35 @@ uint32_t AudioFlinger::PlaybackThread::trackCountForUid_l(uid_t uid) const
		return trackCount;
		}

		bool AudioFlinger::PlaybackThread::checkRunningTimestamp()
		bool AudioFlinger::PlaybackThread::IsTimestampAdvancing::check(AudioStreamOut * output)
		{
		// Check the timestamp to see if it's advancing once every 150ms. If we check too frequently, we
		// could falsely detect that the frame position has stalled due to underrun because we haven't
		// given the Audio HAL enough time to update.
		const nsecs_t nowNs = systemTime();
		if (nowNs - mPreviousNs < mMinimumTimeBetweenChecksNs) {
		return mLatchedValue;
		}
		mPreviousNs = nowNs;
		mLatchedValue = false;
		// Determine if the presentation position is still advancing.
		uint64_t position = 0;
		struct timespec unused;
		const status_t ret = mOutput->getPresentationPosition(&position, &unused);
		const status_t ret = output->getPresentationPosition(&position, &unused);
		if (ret == NO_ERROR) {
		if (position != mLastCheckedTimestampPosition) {
		mLastCheckedTimestampPosition = position;
		return true;
		if (position != mPreviousPosition) {
		mPreviousPosition = position;
		mLatchedValue = true;
		}
		}
		return false;
		return mLatchedValue;
		}

		void AudioFlinger::PlaybackThread::IsTimestampAdvancing::clear()
		{
		mLatchedValue = true;
		mPreviousPosition = 0;
		mPreviousNs = 0;
		}

		// isTrackAllowed_l() must be called with ThreadBase::mLock held
		@@ -6348,9 +6371,9 @@ AudioFlinger::PlaybackThread::mixer_state AudioFlinger::DirectOutputThread::prep
		// No buffers for this track. Give it a few chances to
		// fill a buffer, then remove it from active list.
		// Only consider last track started for mixer state control
		bool isTimestampAdvancing = mIsTimestampAdvancing.check(mOutput);
		if (--(track->mRetryCount) <= 0) {
		const bool running = checkRunningTimestamp();
		if (running) { // still running, give us more time.
		if (isTimestampAdvancing) { // HAL is still playing audio, give us more time.
		track->mRetryCount = kMaxTrackRetriesOffload;
		} else {
		ALOGV("BUFFER TIMEOUT: remove track(%d) from active list", trackId);
		@@ -6931,9 +6954,9 @@ AudioFlinger::PlaybackThread::mixer_state AudioFlinger::OffloadThread::prepareTr
		} else {
		// No buffers for this track. Give it a few chances to
		// fill a buffer, then remove it from active list.
		bool isTimestampAdvancing = mIsTimestampAdvancing.check(mOutput);
		if (--(track->mRetryCount) <= 0) {
		const bool running = checkRunningTimestamp();
		if (running) { // still running, give us more time.
		if (isTimestampAdvancing) { // HAL is still playing audio, give us more time.
		track->mRetryCount = kMaxTrackRetriesOffload;
		} else {
		ALOGV("OffloadThread: BUFFER TIMEOUT: remove track(%d) from active list",

services/audioflinger/Threads.h

+30 −5

Original line number	Diff line number	Diff line
		@@ -1403,13 +1403,38 @@ protected:

		std::atomic_bool mCheckOutputStageEffects{};

		// A differential check on the timestamps to see if there is a change in the
		// timestamp frame position between the last call to checkRunningTimestamp.
		uint64_t mLastCheckedTimestampPosition = ~0LL;

		bool checkRunningTimestamp();
		// Provides periodic checking for timestamp advancement for underrun detection.
		class IsTimestampAdvancing {
		public:
		// The timestamp will not be checked any faster than the specified time.
		IsTimestampAdvancing(nsecs_t minimumTimeBetweenChecksNs)
		: mMinimumTimeBetweenChecksNs(minimumTimeBetweenChecksNs)
		{
		clear();
		}
		// Check if the presentation position has advanced in the last periodic time.
		bool check(AudioStreamOut * output);
		// Clear the internal state when the playback state changes for the output
		// stream.
		void clear();
		private:
		// The minimum time between timestamp checks.
		const nsecs_t mMinimumTimeBetweenChecksNs;
		// Add differential check on the timestamps to see if there is a change in the
		// timestamp frame position between the last call to check.
		uint64_t mPreviousPosition;
		// The time at which the last check occurred, to ensure we don't check too
		// frequently, giving the Audio HAL enough time to update its timestamps.
		nsecs_t mPreviousNs;
		// The valued is latched so we don't check timestamps too frequently.
		bool mLatchedValue;
		};
		IsTimestampAdvancing mIsTimestampAdvancing;

		virtual void flushHw_l() { mLastCheckedTimestampPosition = ~0LL; }
		virtual void flushHw_l() {
		mIsTimestampAdvancing.clear();
		}
		};

		class MixerThread : public PlaybackThread {