1 /*
2  * Copyright (C) 2012 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 // <IMPORTANT_WARNING>
18 // Design rules for threadLoop() are given in the comments at section "Fast mixer thread" of
19 // StateQueue.h.  In particular, avoid library and system calls except at well-known points.
20 // The design rules are only for threadLoop(), and don't apply to FastMixerDumpState methods.
21 // </IMPORTANT_WARNING>
22 
23 #define LOG_TAG "FastMixer"
24 //#define LOG_NDEBUG 0
25 
26 #define ATRACE_TAG ATRACE_TAG_AUDIO
27 
28 #include "Configuration.h"
29 #include <time.h>
30 #include <utils/Debug.h>
31 #include <utils/Log.h>
32 #include <utils/Trace.h>
33 #include <system/audio.h>
34 #ifdef FAST_THREAD_STATISTICS
35 #include <audio_utils/Statistics.h>
36 #ifdef CPU_FREQUENCY_STATISTICS
37 #include <cpustats/ThreadCpuUsage.h>
38 #endif
39 #endif
40 #include <audio_utils/channels.h>
41 #include <audio_utils/format.h>
42 #include <audio_utils/mono_blend.h>
43 #include <cutils/bitops.h>
44 #include <media/AudioMixer.h>
45 #include "FastMixer.h"
46 #include "TypedLogger.h"
47 
48 namespace android {
49 
50 /*static*/ const FastMixerState FastMixer::sInitial;
51 
FastMixer(audio_io_handle_t parentIoHandle)52 FastMixer::FastMixer(audio_io_handle_t parentIoHandle)
53     : FastThread("cycle_ms", "load_us"),
54     // mFastTrackNames
55     // mGenerations
56     mOutputSink(NULL),
57     mOutputSinkGen(0),
58     mMixer(NULL),
59     mSinkBuffer(NULL),
60     mSinkBufferSize(0),
61     mSinkChannelCount(FCC_2),
62     mMixerBuffer(NULL),
63     mMixerBufferSize(0),
64     mMixerBufferState(UNDEFINED),
65     mFormat(Format_Invalid),
66     mSampleRate(0),
67     mFastTracksGen(0),
68     mTotalNativeFramesWritten(0),
69     // timestamp
70     mNativeFramesWrittenButNotPresented(0),   // the = 0 is to silence the compiler
71     mMasterMono(false),
72     mThreadIoHandle(parentIoHandle)
73 {
74     (void)mThreadIoHandle; // prevent unused warning, see C++17 [[maybe_unused]]
75 
76     // FIXME pass sInitial as parameter to base class constructor, and make it static local
77     mPrevious = &sInitial;
78     mCurrent = &sInitial;
79 
80     mDummyDumpState = &mDummyFastMixerDumpState;
81     // TODO: Add channel mask to NBAIO_Format.
82     // We assume that the channel mask must be a valid positional channel mask.
83     mSinkChannelMask = audio_channel_out_mask_from_count(mSinkChannelCount);
84 
85     unsigned i;
86     for (i = 0; i < FastMixerState::sMaxFastTracks; ++i) {
87         mGenerations[i] = 0;
88     }
89 #ifdef FAST_THREAD_STATISTICS
90     mOldLoad.tv_sec = 0;
91     mOldLoad.tv_nsec = 0;
92 #endif
93 }
94 
~FastMixer()95 FastMixer::~FastMixer()
96 {
97 }
98 
sq()99 FastMixerStateQueue* FastMixer::sq()
100 {
101     return &mSQ;
102 }
103 
poll()104 const FastThreadState *FastMixer::poll()
105 {
106     return mSQ.poll();
107 }
108 
setNBLogWriter(NBLog::Writer * logWriter __unused)109 void FastMixer::setNBLogWriter(NBLog::Writer *logWriter __unused)
110 {
111 }
112 
onIdle()113 void FastMixer::onIdle()
114 {
115     mPreIdle = *(const FastMixerState *)mCurrent;
116     mCurrent = &mPreIdle;
117 }
118 
onExit()119 void FastMixer::onExit()
120 {
121     delete mMixer;
122     free(mMixerBuffer);
123     free(mSinkBuffer);
124 }
125 
isSubClassCommand(FastThreadState::Command command)126 bool FastMixer::isSubClassCommand(FastThreadState::Command command)
127 {
128     switch ((FastMixerState::Command) command) {
129     case FastMixerState::MIX:
130     case FastMixerState::WRITE:
131     case FastMixerState::MIX_WRITE:
132         return true;
133     default:
134         return false;
135     }
136 }
137 
updateMixerTrack(int index,Reason reason)138 void FastMixer::updateMixerTrack(int index, Reason reason) {
139     const FastMixerState * const current = (const FastMixerState *) mCurrent;
140     const FastTrack * const fastTrack = &current->mFastTracks[index];
141 
142     // check and update generation
143     if (reason == REASON_MODIFY && mGenerations[index] == fastTrack->mGeneration) {
144         return; // no change on an already configured track.
145     }
146     mGenerations[index] = fastTrack->mGeneration;
147 
148     // mMixer == nullptr on configuration failure (check done after generation update).
149     if (mMixer == nullptr) {
150         return;
151     }
152 
153     switch (reason) {
154     case REASON_REMOVE:
155         mMixer->destroy(index);
156         break;
157     case REASON_ADD: {
158         const status_t status = mMixer->create(
159                 index, fastTrack->mChannelMask, fastTrack->mFormat, AUDIO_SESSION_OUTPUT_MIX);
160         LOG_ALWAYS_FATAL_IF(status != NO_ERROR,
161                 "%s: cannot create fast track index"
162                 " %d, mask %#x, format %#x in AudioMixer",
163                 __func__, index, fastTrack->mChannelMask, fastTrack->mFormat);
164     }
165         [[fallthrough]];  // now fallthrough to update the newly created track.
166     case REASON_MODIFY:
167         mMixer->setBufferProvider(index, fastTrack->mBufferProvider);
168 
169         float vlf, vrf;
170         if (fastTrack->mVolumeProvider != nullptr) {
171             const gain_minifloat_packed_t vlr = fastTrack->mVolumeProvider->getVolumeLR();
172             vlf = float_from_gain(gain_minifloat_unpack_left(vlr));
173             vrf = float_from_gain(gain_minifloat_unpack_right(vlr));
174         } else {
175             vlf = vrf = AudioMixer::UNITY_GAIN_FLOAT;
176         }
177 
178         // set volume to avoid ramp whenever the track is updated (or created).
179         // Note: this does not distinguish from starting fresh or
180         // resuming from a paused state.
181         mMixer->setParameter(index, AudioMixer::VOLUME, AudioMixer::VOLUME0, &vlf);
182         mMixer->setParameter(index, AudioMixer::VOLUME, AudioMixer::VOLUME1, &vrf);
183 
184         mMixer->setParameter(index, AudioMixer::RESAMPLE, AudioMixer::REMOVE, nullptr);
185         mMixer->setParameter(index, AudioMixer::TRACK, AudioMixer::MAIN_BUFFER,
186                 (void *)mMixerBuffer);
187         mMixer->setParameter(index, AudioMixer::TRACK, AudioMixer::MIXER_FORMAT,
188                 (void *)(uintptr_t)mMixerBufferFormat);
189         mMixer->setParameter(index, AudioMixer::TRACK, AudioMixer::FORMAT,
190                 (void *)(uintptr_t)fastTrack->mFormat);
191         mMixer->setParameter(index, AudioMixer::TRACK, AudioMixer::CHANNEL_MASK,
192                 (void *)(uintptr_t)fastTrack->mChannelMask);
193         mMixer->setParameter(index, AudioMixer::TRACK, AudioMixer::MIXER_CHANNEL_MASK,
194                 (void *)(uintptr_t)mSinkChannelMask);
195         mMixer->setParameter(index, AudioMixer::TRACK, AudioMixer::HAPTIC_ENABLED,
196                 (void *)(uintptr_t)fastTrack->mHapticPlaybackEnabled);
197         mMixer->setParameter(index, AudioMixer::TRACK, AudioMixer::HAPTIC_INTENSITY,
198                 (void *)(uintptr_t)fastTrack->mHapticIntensity);
199 
200         mMixer->enable(index);
201         break;
202     default:
203         LOG_ALWAYS_FATAL("%s: invalid update reason %d", __func__, reason);
204     }
205 }
206 
onStateChange()207 void FastMixer::onStateChange()
208 {
209     const FastMixerState * const current = (const FastMixerState *) mCurrent;
210     const FastMixerState * const previous = (const FastMixerState *) mPrevious;
211     FastMixerDumpState * const dumpState = (FastMixerDumpState *) mDumpState;
212     const size_t frameCount = current->mFrameCount;
213 
214     // update boottime offset, in case it has changed
215     mTimestamp.mTimebaseOffset[ExtendedTimestamp::TIMEBASE_BOOTTIME] =
216             mBoottimeOffset.load();
217 
218     // handle state change here, but since we want to diff the state,
219     // we're prepared for previous == &sInitial the first time through
220     unsigned previousTrackMask;
221 
222     // check for change in output HAL configuration
223     NBAIO_Format previousFormat = mFormat;
224     if (current->mOutputSinkGen != mOutputSinkGen) {
225         mOutputSink = current->mOutputSink;
226         mOutputSinkGen = current->mOutputSinkGen;
227         mSinkChannelMask = current->mSinkChannelMask;
228         mBalance.setChannelMask(mSinkChannelMask);
229         if (mOutputSink == NULL) {
230             mFormat = Format_Invalid;
231             mSampleRate = 0;
232             mSinkChannelCount = 0;
233             mSinkChannelMask = AUDIO_CHANNEL_NONE;
234             mAudioChannelCount = 0;
235         } else {
236             mFormat = mOutputSink->format();
237             mSampleRate = Format_sampleRate(mFormat);
238             mSinkChannelCount = Format_channelCount(mFormat);
239             LOG_ALWAYS_FATAL_IF(mSinkChannelCount > AudioMixer::MAX_NUM_CHANNELS);
240 
241             if (mSinkChannelMask == AUDIO_CHANNEL_NONE) {
242                 mSinkChannelMask = audio_channel_out_mask_from_count(mSinkChannelCount);
243             }
244             mAudioChannelCount = mSinkChannelCount - audio_channel_count_from_out_mask(
245                     mSinkChannelMask & AUDIO_CHANNEL_HAPTIC_ALL);
246         }
247         dumpState->mSampleRate = mSampleRate;
248     }
249 
250     if ((!Format_isEqual(mFormat, previousFormat)) || (frameCount != previous->mFrameCount)) {
251         // FIXME to avoid priority inversion, don't delete here
252         delete mMixer;
253         mMixer = NULL;
254         free(mMixerBuffer);
255         mMixerBuffer = NULL;
256         free(mSinkBuffer);
257         mSinkBuffer = NULL;
258         if (frameCount > 0 && mSampleRate > 0) {
259             // FIXME new may block for unbounded time at internal mutex of the heap
260             //       implementation; it would be better to have normal mixer allocate for us
261             //       to avoid blocking here and to prevent possible priority inversion
262             mMixer = new AudioMixer(frameCount, mSampleRate);
263             // FIXME See the other FIXME at FastMixer::setNBLogWriter()
264             NBLog::thread_params_t params;
265             params.frameCount = frameCount;
266             params.sampleRate = mSampleRate;
267             LOG_THREAD_PARAMS(params);
268             const size_t mixerFrameSize = mSinkChannelCount
269                     * audio_bytes_per_sample(mMixerBufferFormat);
270             mMixerBufferSize = mixerFrameSize * frameCount;
271             (void)posix_memalign(&mMixerBuffer, 32, mMixerBufferSize);
272             const size_t sinkFrameSize = mSinkChannelCount
273                     * audio_bytes_per_sample(mFormat.mFormat);
274             if (sinkFrameSize > mixerFrameSize) { // need a sink buffer
275                 mSinkBufferSize = sinkFrameSize * frameCount;
276                 (void)posix_memalign(&mSinkBuffer, 32, mSinkBufferSize);
277             }
278             mPeriodNs = (frameCount * 1000000000LL) / mSampleRate;    // 1.00
279             mUnderrunNs = (frameCount * 1750000000LL) / mSampleRate;  // 1.75
280             mOverrunNs = (frameCount * 500000000LL) / mSampleRate;    // 0.50
281             mForceNs = (frameCount * 950000000LL) / mSampleRate;      // 0.95
282             mWarmupNsMin = (frameCount * 750000000LL) / mSampleRate;  // 0.75
283             mWarmupNsMax = (frameCount * 1250000000LL) / mSampleRate; // 1.25
284         } else {
285             mPeriodNs = 0;
286             mUnderrunNs = 0;
287             mOverrunNs = 0;
288             mForceNs = 0;
289             mWarmupNsMin = 0;
290             mWarmupNsMax = LONG_MAX;
291         }
292         mMixerBufferState = UNDEFINED;
293         // we need to reconfigure all active tracks
294         previousTrackMask = 0;
295         mFastTracksGen = current->mFastTracksGen - 1;
296         dumpState->mFrameCount = frameCount;
297 #ifdef TEE_SINK
298         mTee.set(mFormat, NBAIO_Tee::TEE_FLAG_OUTPUT_THREAD);
299         mTee.setId(std::string("_") + std::to_string(mThreadIoHandle) + "_F");
300 #endif
301     } else {
302         previousTrackMask = previous->mTrackMask;
303     }
304 
305     // check for change in active track set
306     const unsigned currentTrackMask = current->mTrackMask;
307     dumpState->mTrackMask = currentTrackMask;
308     dumpState->mNumTracks = popcount(currentTrackMask);
309     if (current->mFastTracksGen != mFastTracksGen) {
310 
311         // process removed tracks first to avoid running out of track names
312         unsigned removedTracks = previousTrackMask & ~currentTrackMask;
313         while (removedTracks != 0) {
314             int i = __builtin_ctz(removedTracks);
315             removedTracks &= ~(1 << i);
316             updateMixerTrack(i, REASON_REMOVE);
317             // don't reset track dump state, since other side is ignoring it
318         }
319 
320         // now process added tracks
321         unsigned addedTracks = currentTrackMask & ~previousTrackMask;
322         while (addedTracks != 0) {
323             int i = __builtin_ctz(addedTracks);
324             addedTracks &= ~(1 << i);
325             updateMixerTrack(i, REASON_ADD);
326         }
327 
328         // finally process (potentially) modified tracks; these use the same slot
329         // but may have a different buffer provider or volume provider
330         unsigned modifiedTracks = currentTrackMask & previousTrackMask;
331         while (modifiedTracks != 0) {
332             int i = __builtin_ctz(modifiedTracks);
333             modifiedTracks &= ~(1 << i);
334             updateMixerTrack(i, REASON_MODIFY);
335         }
336 
337         mFastTracksGen = current->mFastTracksGen;
338     }
339 }
340 
onWork()341 void FastMixer::onWork()
342 {
343     // TODO: pass an ID parameter to indicate which time series we want to write to in NBLog.cpp
344     // Or: pass both of these into a single call with a boolean
345     const FastMixerState * const current = (const FastMixerState *) mCurrent;
346     FastMixerDumpState * const dumpState = (FastMixerDumpState *) mDumpState;
347 
348     if (mIsWarm) {
349         // Logging timestamps for FastMixer is currently disabled to make memory room for logging
350         // other statistics in FastMixer.
351         // To re-enable, delete the #ifdef FASTMIXER_LOG_HIST_TS lines (and the #endif lines).
352 #ifdef FASTMIXER_LOG_HIST_TS
353         LOG_HIST_TS();
354 #endif
355         //ALOGD("Eric FastMixer::onWork() mIsWarm");
356     } else {
357         dumpState->mTimestampVerifier.discontinuity();
358         // See comment in if block.
359 #ifdef FASTMIXER_LOG_HIST_TS
360         LOG_AUDIO_STATE();
361 #endif
362     }
363     const FastMixerState::Command command = mCommand;
364     const size_t frameCount = current->mFrameCount;
365 
366     if ((command & FastMixerState::MIX) && (mMixer != NULL) && mIsWarm) {
367         ALOG_ASSERT(mMixerBuffer != NULL);
368 
369         // AudioMixer::mState.enabledTracks is undefined if mState.hook == process__validate,
370         // so we keep a side copy of enabledTracks
371         bool anyEnabledTracks = false;
372 
373         // for each track, update volume and check for underrun
374         unsigned currentTrackMask = current->mTrackMask;
375         while (currentTrackMask != 0) {
376             int i = __builtin_ctz(currentTrackMask);
377             currentTrackMask &= ~(1 << i);
378             const FastTrack* fastTrack = &current->mFastTracks[i];
379 
380             const int64_t trackFramesWrittenButNotPresented =
381                 mNativeFramesWrittenButNotPresented;
382             const int64_t trackFramesWritten = fastTrack->mBufferProvider->framesReleased();
383             ExtendedTimestamp perTrackTimestamp(mTimestamp);
384 
385             // Can't provide an ExtendedTimestamp before first frame presented.
386             // Also, timestamp may not go to very last frame on stop().
387             if (trackFramesWritten >= trackFramesWrittenButNotPresented &&
388                     perTrackTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] > 0) {
389                 perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] =
390                         trackFramesWritten - trackFramesWrittenButNotPresented;
391             } else {
392                 perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] = 0;
393                 perTrackTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] = -1;
394             }
395             perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_SERVER] = trackFramesWritten;
396             fastTrack->mBufferProvider->onTimestamp(perTrackTimestamp);
397 
398             const int name = i;
399             if (fastTrack->mVolumeProvider != NULL) {
400                 gain_minifloat_packed_t vlr = fastTrack->mVolumeProvider->getVolumeLR();
401                 float vlf = float_from_gain(gain_minifloat_unpack_left(vlr));
402                 float vrf = float_from_gain(gain_minifloat_unpack_right(vlr));
403 
404                 mMixer->setParameter(name, AudioMixer::RAMP_VOLUME, AudioMixer::VOLUME0, &vlf);
405                 mMixer->setParameter(name, AudioMixer::RAMP_VOLUME, AudioMixer::VOLUME1, &vrf);
406             }
407             // FIXME The current implementation of framesReady() for fast tracks
408             // takes a tryLock, which can block
409             // up to 1 ms.  If enough active tracks all blocked in sequence, this would result
410             // in the overall fast mix cycle being delayed.  Should use a non-blocking FIFO.
411             size_t framesReady = fastTrack->mBufferProvider->framesReady();
412             if (ATRACE_ENABLED()) {
413                 // I wish we had formatted trace names
414                 char traceName[16];
415                 strcpy(traceName, "fRdy");
416                 traceName[4] = i + (i < 10 ? '0' : 'A' - 10);
417                 traceName[5] = '\0';
418                 ATRACE_INT(traceName, framesReady);
419             }
420             FastTrackDump *ftDump = &dumpState->mTracks[i];
421             FastTrackUnderruns underruns = ftDump->mUnderruns;
422             if (framesReady < frameCount) {
423                 if (framesReady == 0) {
424                     underruns.mBitFields.mEmpty++;
425                     underruns.mBitFields.mMostRecent = UNDERRUN_EMPTY;
426                     mMixer->disable(name);
427                 } else {
428                     // allow mixing partial buffer
429                     underruns.mBitFields.mPartial++;
430                     underruns.mBitFields.mMostRecent = UNDERRUN_PARTIAL;
431                     mMixer->enable(name);
432                     anyEnabledTracks = true;
433                 }
434             } else {
435                 underruns.mBitFields.mFull++;
436                 underruns.mBitFields.mMostRecent = UNDERRUN_FULL;
437                 mMixer->enable(name);
438                 anyEnabledTracks = true;
439             }
440             ftDump->mUnderruns = underruns;
441             ftDump->mFramesReady = framesReady;
442             ftDump->mFramesWritten = trackFramesWritten;
443         }
444 
445         if (anyEnabledTracks) {
446             // process() is CPU-bound
447             mMixer->process();
448             mMixerBufferState = MIXED;
449         } else if (mMixerBufferState != ZEROED) {
450             mMixerBufferState = UNDEFINED;
451         }
452 
453     } else if (mMixerBufferState == MIXED) {
454         mMixerBufferState = UNDEFINED;
455     }
456     //bool didFullWrite = false;    // dumpsys could display a count of partial writes
457     if ((command & FastMixerState::WRITE) && (mOutputSink != NULL) && (mMixerBuffer != NULL)) {
458         if (mMixerBufferState == UNDEFINED) {
459             memset(mMixerBuffer, 0, mMixerBufferSize);
460             mMixerBufferState = ZEROED;
461         }
462 
463         if (mMasterMono.load()) {  // memory_order_seq_cst
464             mono_blend(mMixerBuffer, mMixerBufferFormat, Format_channelCount(mFormat), frameCount,
465                     true /*limit*/);
466         }
467 
468         // Balance must take effect after mono conversion.
469         // mBalance detects zero balance within the class for speed (not needed here).
470         mBalance.setBalance(mMasterBalance.load());
471         mBalance.process((float *)mMixerBuffer, frameCount);
472 
473         // prepare the buffer used to write to sink
474         void *buffer = mSinkBuffer != NULL ? mSinkBuffer : mMixerBuffer;
475         if (mFormat.mFormat != mMixerBufferFormat) { // sink format not the same as mixer format
476             memcpy_by_audio_format(buffer, mFormat.mFormat, mMixerBuffer, mMixerBufferFormat,
477                     frameCount * Format_channelCount(mFormat));
478         }
479         if (mSinkChannelMask & AUDIO_CHANNEL_HAPTIC_ALL) {
480             // When there are haptic channels, the sample data is partially interleaved.
481             // Make the sample data fully interleaved here.
482             adjust_channels_non_destructive(buffer, mAudioChannelCount, buffer, mSinkChannelCount,
483                     audio_bytes_per_sample(mFormat.mFormat),
484                     frameCount * audio_bytes_per_frame(mAudioChannelCount, mFormat.mFormat));
485         }
486         // if non-NULL, then duplicate write() to this non-blocking sink
487 #ifdef TEE_SINK
488         mTee.write(buffer, frameCount);
489 #endif
490         // FIXME write() is non-blocking and lock-free for a properly implemented NBAIO sink,
491         //       but this code should be modified to handle both non-blocking and blocking sinks
492         dumpState->mWriteSequence++;
493         ATRACE_BEGIN("write");
494         ssize_t framesWritten = mOutputSink->write(buffer, frameCount);
495         ATRACE_END();
496         dumpState->mWriteSequence++;
497         if (framesWritten >= 0) {
498             ALOG_ASSERT((size_t) framesWritten <= frameCount);
499             mTotalNativeFramesWritten += framesWritten;
500             dumpState->mFramesWritten = mTotalNativeFramesWritten;
501             //if ((size_t) framesWritten == frameCount) {
502             //    didFullWrite = true;
503             //}
504         } else {
505             dumpState->mWriteErrors++;
506         }
507         mAttemptedWrite = true;
508         // FIXME count # of writes blocked excessively, CPU usage, etc. for dump
509 
510         if (mIsWarm) {
511             ExtendedTimestamp timestamp; // local
512             status_t status = mOutputSink->getTimestamp(timestamp);
513             if (status == NO_ERROR) {
514                 dumpState->mTimestampVerifier.add(
515                         timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL],
516                         timestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL],
517                         mSampleRate);
518                 const int64_t totalNativeFramesPresented =
519                         timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL];
520                 if (totalNativeFramesPresented <= mTotalNativeFramesWritten) {
521                     mNativeFramesWrittenButNotPresented =
522                         mTotalNativeFramesWritten - totalNativeFramesPresented;
523                     mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] =
524                             timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL];
525                     mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] =
526                             timestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL];
527                     // We don't compensate for server - kernel time difference and
528                     // only update latency if we have valid info.
529                     const double latencyMs =
530                             (double)mNativeFramesWrittenButNotPresented * 1000 / mSampleRate;
531                     dumpState->mLatencyMs = latencyMs;
532                     LOG_LATENCY(latencyMs);
533                 } else {
534                     // HAL reported that more frames were presented than were written
535                     mNativeFramesWrittenButNotPresented = 0;
536                     status = INVALID_OPERATION;
537                 }
538             } else {
539                 dumpState->mTimestampVerifier.error();
540             }
541             if (status == NO_ERROR) {
542                 mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_SERVER] =
543                         mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL];
544             } else {
545                 // fetch server time if we can't get timestamp
546                 mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_SERVER] =
547                         systemTime(SYSTEM_TIME_MONOTONIC);
548                 // clear out kernel cached position as this may get rapidly stale
549                 // if we never get a new valid timestamp
550                 mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] = 0;
551                 mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] = -1;
552             }
553         }
554     }
555 }
556 
557 }   // namespace android
558