VirtualDisplaySurface.cpp revision febd4f4f462444bfcb3f0618d07ac77e3fc1f6ad 
1/*
2 * Copyright 2013 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// #define LOG_NDEBUG 0
18#include "VirtualDisplaySurface.h"
19#include "HWComposer.h"
20
21// ---------------------------------------------------------------------------
22namespace android {
23// ---------------------------------------------------------------------------
24
25#if defined(FORCE_HWC_COPY_FOR_VIRTUAL_DISPLAYS)
26static const bool sForceHwcCopy = true;
27#else
28static const bool sForceHwcCopy = false;
29#endif
30
31#define VDS_LOGE(msg, ...) ALOGE("[%s] "msg, \
32        mDisplayName.string(), ##__VA_ARGS__)
33#define VDS_LOGW_IF(cond, msg, ...) ALOGW_IF(cond, "[%s] "msg, \
34        mDisplayName.string(), ##__VA_ARGS__)
35#define VDS_LOGV(msg, ...) ALOGV("[%s] "msg, \
36        mDisplayName.string(), ##__VA_ARGS__)
37
38static const char* dbgCompositionTypeStr(DisplaySurface::CompositionType type) {
39    switch (type) {
40        case DisplaySurface::COMPOSITION_UNKNOWN: return "UNKNOWN";
41        case DisplaySurface::COMPOSITION_GLES:    return "GLES";
42        case DisplaySurface::COMPOSITION_HWC:     return "HWC";
43        case DisplaySurface::COMPOSITION_MIXED:   return "MIXED";
44        default:                                  return "<INVALID>";
45    }
46}
47
48VirtualDisplaySurface::VirtualDisplaySurface(HWComposer& hwc, int32_t dispId,
49        const sp<IGraphicBufferProducer>& sink,
50        const sp<IGraphicBufferProducer>& bqProducer,
51        const sp<IGraphicBufferConsumer>& bqConsumer,
52        const String8& name)
53:   ConsumerBase(bqConsumer),
54    mHwc(hwc),
55    mDisplayId(dispId),
56    mDisplayName(name),
57    mOutputUsage(GRALLOC_USAGE_HW_COMPOSER),
58    mProducerSlotSource(0),
59    mDbgState(DBG_STATE_IDLE),
60    mDbgLastCompositionType(COMPOSITION_UNKNOWN),
61    mMustRecompose(false)
62{
63    mSource[SOURCE_SINK] = sink;
64    mSource[SOURCE_SCRATCH] = bqProducer;
65
66    resetPerFrameState();
67
68    int sinkWidth, sinkHeight;
69    sink->query(NATIVE_WINDOW_WIDTH, &sinkWidth);
70    sink->query(NATIVE_WINDOW_HEIGHT, &sinkHeight);
71
72    // Pick the buffer format to request from the sink when not rendering to it
73    // with GLES. If the consumer needs CPU access, use the default format
74    // set by the consumer. Otherwise allow gralloc to decide the format based
75    // on usage bits.
76    int sinkUsage;
77    sink->query(NATIVE_WINDOW_CONSUMER_USAGE_BITS, &sinkUsage);
78    if (sinkUsage & (GRALLOC_USAGE_SW_READ_MASK | GRALLOC_USAGE_SW_WRITE_MASK)) {
79        int sinkFormat;
80        sink->query(NATIVE_WINDOW_FORMAT, &sinkFormat);
81        mDefaultOutputFormat = sinkFormat;
82    } else {
83        mDefaultOutputFormat = HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED;
84    }
85    mOutputFormat = mDefaultOutputFormat;
86
87    ConsumerBase::mName = String8::format("VDS: %s", mDisplayName.string());
88    mConsumer->setConsumerName(ConsumerBase::mName);
89    mConsumer->setConsumerUsageBits(GRALLOC_USAGE_HW_COMPOSER);
90    mConsumer->setDefaultBufferSize(sinkWidth, sinkHeight);
91    mConsumer->setDefaultMaxBufferCount(2);
92}
93
94VirtualDisplaySurface::~VirtualDisplaySurface() {
95}
96
97status_t VirtualDisplaySurface::beginFrame(bool mustRecompose) {
98    if (mDisplayId < 0)
99        return NO_ERROR;
100
101    mMustRecompose = mustRecompose;
102
103    VDS_LOGW_IF(mDbgState != DBG_STATE_IDLE,
104            "Unexpected beginFrame() in %s state", dbgStateStr());
105    mDbgState = DBG_STATE_BEGUN;
106
107    uint32_t transformHint, numPendingBuffers;
108    mQueueBufferOutput.deflate(&mSinkBufferWidth, &mSinkBufferHeight,
109            &transformHint, &numPendingBuffers);
110
111    return refreshOutputBuffer();
112}
113
114status_t VirtualDisplaySurface::prepareFrame(CompositionType compositionType) {
115    if (mDisplayId < 0)
116        return NO_ERROR;
117
118    VDS_LOGW_IF(mDbgState != DBG_STATE_BEGUN,
119            "Unexpected prepareFrame() in %s state", dbgStateStr());
120    mDbgState = DBG_STATE_PREPARED;
121
122    mCompositionType = compositionType;
123    if (sForceHwcCopy && mCompositionType == COMPOSITION_GLES) {
124        // Some hardware can do RGB->YUV conversion more efficiently in hardware
125        // controlled by HWC than in hardware controlled by the video encoder.
126        // Forcing GLES-composed frames to go through an extra copy by the HWC
127        // allows the format conversion to happen there, rather than passing RGB
128        // directly to the consumer.
129        //
130        // On the other hand, when the consumer prefers RGB or can consume RGB
131        // inexpensively, this forces an unnecessary copy.
132        mCompositionType = COMPOSITION_MIXED;
133    }
134
135    if (mCompositionType != mDbgLastCompositionType) {
136        VDS_LOGV("prepareFrame: composition type changed to %s",
137                dbgCompositionTypeStr(mCompositionType));
138        mDbgLastCompositionType = mCompositionType;
139    }
140
141    if (mCompositionType != COMPOSITION_GLES &&
142            (mOutputFormat != mDefaultOutputFormat ||
143             mOutputUsage != GRALLOC_USAGE_HW_COMPOSER)) {
144        // We must have just switched from GLES-only to MIXED or HWC
145        // composition. Stop using the format and usage requested by the GLES
146        // driver; they may be suboptimal when HWC is writing to the output
147        // buffer. For example, if the output is going to a video encoder, and
148        // HWC can write directly to YUV, some hardware can skip a
149        // memory-to-memory RGB-to-YUV conversion step.
150        //
151        // If we just switched *to* GLES-only mode, we'll change the
152        // format/usage and get a new buffer when the GLES driver calls
153        // dequeueBuffer().
154        mOutputFormat = mDefaultOutputFormat;
155        mOutputUsage = GRALLOC_USAGE_HW_COMPOSER;
156        refreshOutputBuffer();
157    }
158
159    return NO_ERROR;
160}
161
162status_t VirtualDisplaySurface::compositionComplete() {
163    return NO_ERROR;
164}
165
166status_t VirtualDisplaySurface::advanceFrame() {
167    if (mDisplayId < 0)
168        return NO_ERROR;
169
170    if (mCompositionType == COMPOSITION_HWC) {
171        VDS_LOGW_IF(mDbgState != DBG_STATE_PREPARED,
172                "Unexpected advanceFrame() in %s state on HWC frame",
173                dbgStateStr());
174    } else {
175        VDS_LOGW_IF(mDbgState != DBG_STATE_GLES_DONE,
176                "Unexpected advanceFrame() in %s state on GLES/MIXED frame",
177                dbgStateStr());
178    }
179    mDbgState = DBG_STATE_HWC;
180
181    if (mOutputProducerSlot < 0 ||
182            (mCompositionType != COMPOSITION_HWC && mFbProducerSlot < 0)) {
183        // Last chance bailout if something bad happened earlier. For example,
184        // in a GLES configuration, if the sink disappears then dequeueBuffer
185        // will fail, the GLES driver won't queue a buffer, but SurfaceFlinger
186        // will soldier on. So we end up here without a buffer. There should
187        // be lots of scary messages in the log just before this.
188        VDS_LOGE("advanceFrame: no buffer, bailing out");
189        return NO_MEMORY;
190    }
191
192    sp<GraphicBuffer> fbBuffer = mFbProducerSlot >= 0 ?
193            mProducerBuffers[mFbProducerSlot] : sp<GraphicBuffer>(NULL);
194    sp<GraphicBuffer> outBuffer = mProducerBuffers[mOutputProducerSlot];
195    VDS_LOGV("advanceFrame: fb=%d(%p) out=%d(%p)",
196            mFbProducerSlot, fbBuffer.get(),
197            mOutputProducerSlot, outBuffer.get());
198
199    // At this point we know the output buffer acquire fence,
200    // so update HWC state with it.
201    mHwc.setOutputBuffer(mDisplayId, mOutputFence, outBuffer);
202
203    status_t result = NO_ERROR;
204    if (fbBuffer != NULL) {
205        result = mHwc.fbPost(mDisplayId, mFbFence, fbBuffer);
206    }
207
208    return result;
209}
210
211void VirtualDisplaySurface::onFrameCommitted() {
212    if (mDisplayId < 0)
213        return;
214
215    VDS_LOGW_IF(mDbgState != DBG_STATE_HWC,
216            "Unexpected onFrameCommitted() in %s state", dbgStateStr());
217    mDbgState = DBG_STATE_IDLE;
218
219    sp<Fence> fbFence = mHwc.getAndResetReleaseFence(mDisplayId);
220    if (mCompositionType == COMPOSITION_MIXED && mFbProducerSlot >= 0) {
221        // release the scratch buffer back to the pool
222        Mutex::Autolock lock(mMutex);
223        int sslot = mapProducer2SourceSlot(SOURCE_SCRATCH, mFbProducerSlot);
224        VDS_LOGV("onFrameCommitted: release scratch sslot=%d", sslot);
225        addReleaseFenceLocked(sslot, mProducerBuffers[mFbProducerSlot], fbFence);
226        releaseBufferLocked(sslot, mProducerBuffers[mFbProducerSlot],
227                EGL_NO_DISPLAY, EGL_NO_SYNC_KHR);
228    }
229
230    if (mOutputProducerSlot >= 0) {
231        int sslot = mapProducer2SourceSlot(SOURCE_SINK, mOutputProducerSlot);
232        QueueBufferOutput qbo;
233        sp<Fence> outFence = mHwc.getLastRetireFence(mDisplayId);
234        VDS_LOGV("onFrameCommitted: queue sink sslot=%d", sslot);
235        if (mMustRecompose) {
236            status_t result = mSource[SOURCE_SINK]->queueBuffer(sslot,
237                    QueueBufferInput(
238                        systemTime(), false /* isAutoTimestamp */,
239                        Rect(mSinkBufferWidth, mSinkBufferHeight),
240                        NATIVE_WINDOW_SCALING_MODE_FREEZE, 0 /* transform */,
241                        true /* async*/,
242                        outFence),
243                    &qbo);
244            if (result == NO_ERROR) {
245                updateQueueBufferOutput(qbo);
246            }
247        } else {
248            // If the surface hadn't actually been updated, then we only went
249            // through the motions of updating the display to keep our state
250            // machine happy. We cancel the buffer to avoid triggering another
251            // re-composition and causing an infinite loop.
252            mSource[SOURCE_SINK]->cancelBuffer(sslot, outFence);
253        }
254    }
255
256    resetPerFrameState();
257}
258
259void VirtualDisplaySurface::dump(String8& /* result */) const {
260}
261
262status_t VirtualDisplaySurface::requestBuffer(int pslot,
263        sp<GraphicBuffer>* outBuf) {
264    VDS_LOGW_IF(mDbgState != DBG_STATE_GLES,
265            "Unexpected requestBuffer pslot=%d in %s state",
266            pslot, dbgStateStr());
267
268    *outBuf = mProducerBuffers[pslot];
269    return NO_ERROR;
270}
271
272status_t VirtualDisplaySurface::setBufferCount(int bufferCount) {
273    return mSource[SOURCE_SINK]->setBufferCount(bufferCount);
274}
275
276status_t VirtualDisplaySurface::dequeueBuffer(Source source,
277        uint32_t format, uint32_t usage, int* sslot, sp<Fence>* fence) {
278    // Don't let a slow consumer block us
279    bool async = (source == SOURCE_SINK);
280
281    status_t result = mSource[source]->dequeueBuffer(sslot, fence, async,
282            mSinkBufferWidth, mSinkBufferHeight, format, usage);
283    if (result < 0)
284        return result;
285    int pslot = mapSource2ProducerSlot(source, *sslot);
286    VDS_LOGV("dequeueBuffer(%s): sslot=%d pslot=%d result=%d",
287            dbgSourceStr(source), *sslot, pslot, result);
288    uint64_t sourceBit = static_cast<uint64_t>(source) << pslot;
289
290    if ((mProducerSlotSource & (1ULL << pslot)) != sourceBit) {
291        // This slot was previously dequeued from the other source; must
292        // re-request the buffer.
293        result |= BUFFER_NEEDS_REALLOCATION;
294        mProducerSlotSource &= ~(1ULL << pslot);
295        mProducerSlotSource |= sourceBit;
296    }
297
298    if (result & RELEASE_ALL_BUFFERS) {
299        for (uint32_t i = 0; i < BufferQueue::NUM_BUFFER_SLOTS; i++) {
300            if ((mProducerSlotSource & (1ULL << i)) == sourceBit)
301                mProducerBuffers[i].clear();
302        }
303    }
304    if (result & BUFFER_NEEDS_REALLOCATION) {
305        mSource[source]->requestBuffer(*sslot, &mProducerBuffers[pslot]);
306        VDS_LOGV("dequeueBuffer(%s): buffers[%d]=%p fmt=%d usage=%#x",
307                dbgSourceStr(source), pslot, mProducerBuffers[pslot].get(),
308                mProducerBuffers[pslot]->getPixelFormat(),
309                mProducerBuffers[pslot]->getUsage());
310    }
311
312    return result;
313}
314
315status_t VirtualDisplaySurface::dequeueBuffer(int* pslot, sp<Fence>* fence, bool async,
316        uint32_t w, uint32_t h, uint32_t format, uint32_t usage) {
317    VDS_LOGW_IF(mDbgState != DBG_STATE_PREPARED,
318            "Unexpected dequeueBuffer() in %s state", dbgStateStr());
319    mDbgState = DBG_STATE_GLES;
320
321    VDS_LOGW_IF(!async, "EGL called dequeueBuffer with !async despite eglSwapInterval(0)");
322    VDS_LOGV("dequeueBuffer %dx%d fmt=%d usage=%#x", w, h, format, usage);
323
324    status_t result = NO_ERROR;
325    Source source = fbSourceForCompositionType(mCompositionType);
326
327    if (source == SOURCE_SINK) {
328
329        if (mOutputProducerSlot < 0) {
330            // Last chance bailout if something bad happened earlier. For example,
331            // in a GLES configuration, if the sink disappears then dequeueBuffer
332            // will fail, the GLES driver won't queue a buffer, but SurfaceFlinger
333            // will soldier on. So we end up here without a buffer. There should
334            // be lots of scary messages in the log just before this.
335            VDS_LOGE("dequeueBuffer: no buffer, bailing out");
336            return NO_MEMORY;
337        }
338
339        // We already dequeued the output buffer. If the GLES driver wants
340        // something incompatible, we have to cancel and get a new one. This
341        // will mean that HWC will see a different output buffer between
342        // prepare and set, but since we're in GLES-only mode already it
343        // shouldn't matter.
344
345        usage |= GRALLOC_USAGE_HW_COMPOSER;
346        const sp<GraphicBuffer>& buf = mProducerBuffers[mOutputProducerSlot];
347        if ((usage & ~buf->getUsage()) != 0 ||
348                (format != 0 && format != (uint32_t)buf->getPixelFormat()) ||
349                (w != 0 && w != mSinkBufferWidth) ||
350                (h != 0 && h != mSinkBufferHeight)) {
351            VDS_LOGV("dequeueBuffer: dequeueing new output buffer: "
352                    "want %dx%d fmt=%d use=%#x, "
353                    "have %dx%d fmt=%d use=%#x",
354                    w, h, format, usage,
355                    mSinkBufferWidth, mSinkBufferHeight,
356                    buf->getPixelFormat(), buf->getUsage());
357            mOutputFormat = format;
358            mOutputUsage = usage;
359            result = refreshOutputBuffer();
360            if (result < 0)
361                return result;
362        }
363    }
364
365    if (source == SOURCE_SINK) {
366        *pslot = mOutputProducerSlot;
367        *fence = mOutputFence;
368    } else {
369        int sslot;
370        result = dequeueBuffer(source, format, usage, &sslot, fence);
371        if (result >= 0) {
372            *pslot = mapSource2ProducerSlot(source, sslot);
373        }
374    }
375    return result;
376}
377
378status_t VirtualDisplaySurface::detachBuffer(int /* slot */) {
379    VDS_LOGE("detachBuffer is not available for VirtualDisplaySurface");
380    return INVALID_OPERATION;
381}
382
383status_t VirtualDisplaySurface::attachBuffer(int* /* outSlot */,
384        const sp<GraphicBuffer>& /* buffer */) {
385    VDS_LOGE("attachBuffer is not available for VirtualDisplaySurface");
386    return INVALID_OPERATION;
387}
388
389status_t VirtualDisplaySurface::queueBuffer(int pslot,
390        const QueueBufferInput& input, QueueBufferOutput* output) {
391    VDS_LOGW_IF(mDbgState != DBG_STATE_GLES,
392            "Unexpected queueBuffer(pslot=%d) in %s state", pslot,
393            dbgStateStr());
394    mDbgState = DBG_STATE_GLES_DONE;
395
396    VDS_LOGV("queueBuffer pslot=%d", pslot);
397
398    status_t result;
399    if (mCompositionType == COMPOSITION_MIXED) {
400        // Queue the buffer back into the scratch pool
401        QueueBufferOutput scratchQBO;
402        int sslot = mapProducer2SourceSlot(SOURCE_SCRATCH, pslot);
403        result = mSource[SOURCE_SCRATCH]->queueBuffer(sslot, input, &scratchQBO);
404        if (result != NO_ERROR)
405            return result;
406
407        // Now acquire the buffer from the scratch pool -- should be the same
408        // slot and fence as we just queued.
409        Mutex::Autolock lock(mMutex);
410        BufferQueue::BufferItem item;
411        result = acquireBufferLocked(&item, 0);
412        if (result != NO_ERROR)
413            return result;
414        VDS_LOGW_IF(item.mBuf != sslot,
415                "queueBuffer: acquired sslot %d from SCRATCH after queueing sslot %d",
416                item.mBuf, sslot);
417        mFbProducerSlot = mapSource2ProducerSlot(SOURCE_SCRATCH, item.mBuf);
418        mFbFence = mSlots[item.mBuf].mFence;
419
420    } else {
421        LOG_FATAL_IF(mCompositionType != COMPOSITION_GLES,
422                "Unexpected queueBuffer in state %s for compositionType %s",
423                dbgStateStr(), dbgCompositionTypeStr(mCompositionType));
424
425        // Extract the GLES release fence for HWC to acquire
426        int64_t timestamp;
427        bool isAutoTimestamp;
428        Rect crop;
429        int scalingMode;
430        uint32_t transform;
431        bool async;
432        input.deflate(&timestamp, &isAutoTimestamp, &crop, &scalingMode,
433                &transform, &async, &mFbFence);
434
435        mFbProducerSlot = pslot;
436        mOutputFence = mFbFence;
437    }
438
439    *output = mQueueBufferOutput;
440    return NO_ERROR;
441}
442
443void VirtualDisplaySurface::cancelBuffer(int pslot, const sp<Fence>& fence) {
444    VDS_LOGW_IF(mDbgState != DBG_STATE_GLES,
445            "Unexpected cancelBuffer(pslot=%d) in %s state", pslot,
446            dbgStateStr());
447    VDS_LOGV("cancelBuffer pslot=%d", pslot);
448    Source source = fbSourceForCompositionType(mCompositionType);
449    return mSource[source]->cancelBuffer(
450            mapProducer2SourceSlot(source, pslot), fence);
451}
452
453int VirtualDisplaySurface::query(int what, int* value) {
454    return mSource[SOURCE_SINK]->query(what, value);
455}
456
457status_t VirtualDisplaySurface::connect(const sp<IBinder>& token,
458        int api, bool producerControlledByApp,
459        QueueBufferOutput* output) {
460    QueueBufferOutput qbo;
461    status_t result = mSource[SOURCE_SINK]->connect(token, api, producerControlledByApp, &qbo);
462    if (result == NO_ERROR) {
463        updateQueueBufferOutput(qbo);
464        *output = mQueueBufferOutput;
465    }
466    return result;
467}
468
469status_t VirtualDisplaySurface::disconnect(int api) {
470    return mSource[SOURCE_SINK]->disconnect(api);
471}
472
473status_t VirtualDisplaySurface::setSidebandStream(const sp<NativeHandle>& /*stream*/) {
474    return INVALID_OPERATION;
475}
476
477void VirtualDisplaySurface::updateQueueBufferOutput(
478        const QueueBufferOutput& qbo) {
479    uint32_t w, h, transformHint, numPendingBuffers;
480    qbo.deflate(&w, &h, &transformHint, &numPendingBuffers);
481    mQueueBufferOutput.inflate(w, h, 0, numPendingBuffers);
482}
483
484void VirtualDisplaySurface::resetPerFrameState() {
485    mCompositionType = COMPOSITION_UNKNOWN;
486    mSinkBufferWidth = 0;
487    mSinkBufferHeight = 0;
488    mFbFence = Fence::NO_FENCE;
489    mOutputFence = Fence::NO_FENCE;
490    mOutputProducerSlot = -1;
491    mFbProducerSlot = -1;
492}
493
494status_t VirtualDisplaySurface::refreshOutputBuffer() {
495    if (mOutputProducerSlot >= 0) {
496        mSource[SOURCE_SINK]->cancelBuffer(
497                mapProducer2SourceSlot(SOURCE_SINK, mOutputProducerSlot),
498                mOutputFence);
499    }
500
501    int sslot;
502    status_t result = dequeueBuffer(SOURCE_SINK, mOutputFormat, mOutputUsage,
503            &sslot, &mOutputFence);
504    if (result < 0)
505        return result;
506    mOutputProducerSlot = mapSource2ProducerSlot(SOURCE_SINK, sslot);
507
508    // On GLES-only frames, we don't have the right output buffer acquire fence
509    // until after GLES calls queueBuffer(). So here we just set the buffer
510    // (for use in HWC prepare) but not the fence; we'll call this again with
511    // the proper fence once we have it.
512    result = mHwc.setOutputBuffer(mDisplayId, Fence::NO_FENCE,
513            mProducerBuffers[mOutputProducerSlot]);
514
515    return result;
516}
517
518// This slot mapping function is its own inverse, so two copies are unnecessary.
519// Both are kept to make the intent clear where the function is called, and for
520// the (unlikely) chance that we switch to a different mapping function.
521int VirtualDisplaySurface::mapSource2ProducerSlot(Source source, int sslot) {
522    if (source == SOURCE_SCRATCH) {
523        return BufferQueue::NUM_BUFFER_SLOTS - sslot - 1;
524    } else {
525        return sslot;
526    }
527}
528int VirtualDisplaySurface::mapProducer2SourceSlot(Source source, int pslot) {
529    return mapSource2ProducerSlot(source, pslot);
530}
531
532VirtualDisplaySurface::Source
533VirtualDisplaySurface::fbSourceForCompositionType(CompositionType type) {
534    return type == COMPOSITION_MIXED ? SOURCE_SCRATCH : SOURCE_SINK;
535}
536
537const char* VirtualDisplaySurface::dbgStateStr() const {
538    switch (mDbgState) {
539        case DBG_STATE_IDLE:      return "IDLE";
540        case DBG_STATE_PREPARED:  return "PREPARED";
541        case DBG_STATE_GLES:      return "GLES";
542        case DBG_STATE_GLES_DONE: return "GLES_DONE";
543        case DBG_STATE_HWC:       return "HWC";
544        default:                  return "INVALID";
545    }
546}
547
548const char* VirtualDisplaySurface::dbgSourceStr(Source s) {
549    switch (s) {
550        case SOURCE_SINK:    return "SINK";
551        case SOURCE_SCRATCH: return "SCRATCH";
552        default:             return "INVALID";
553    }
554}
555
556// ---------------------------------------------------------------------------
557} // namespace android
558// ---------------------------------------------------------------------------
559