libs/gui/BufferQueueConsumer.cpp - third_party/android/platform/frameworks/native - Git at Google

 /*
  * Copyright 2014 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <inttypes.h>

 #define LOG_TAG "BufferQueueConsumer"
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
 //#define LOG_NDEBUG 0

 #include <gui/BufferItem.h>
 #include <gui/BufferQueueConsumer.h>
 #include <gui/BufferQueueCore.h>
 #include <gui/IConsumerListener.h>
 #include <gui/IProducerListener.h>

 namespace android {

 BufferQueueConsumer::BufferQueueConsumer(const sp<BufferQueueCore>& core) :
     mCore(core),
     mSlots(core->mSlots),
     mConsumerName() {}

 BufferQueueConsumer::~BufferQueueConsumer() {}

 status_t BufferQueueConsumer::acquireBuffer(BufferItem* outBuffer,
         nsecs_t expectedPresent) {
     ATRACE_CALL();
     Mutex::Autolock lock(mCore->mMutex);

     // Check that the consumer doesn't currently have the maximum number of
     // buffers acquired. We allow the max buffer count to be exceeded by one
     // buffer so that the consumer can successfully set up the newly acquired
     // buffer before releasing the old one.
     int numAcquiredBuffers = 0;
     for (int s = 0; s < BufferQueueDefs::NUM_BUFFER_SLOTS; ++s) {
         if (mSlots[s].mBufferState == BufferSlot::ACQUIRED) {
             ++numAcquiredBuffers;
         }
     }
     if (numAcquiredBuffers >= mCore->mMaxAcquiredBufferCount + 1) {
         BQ_LOGE("acquireBuffer: max acquired buffer count reached: %d (max %d)",
                 numAcquiredBuffers, mCore->mMaxAcquiredBufferCount);
         return INVALID_OPERATION;
     }

     // Check if the queue is empty.
     // In asynchronous mode the list is guaranteed to be one buffer deep,
     // while in synchronous mode we use the oldest buffer.
     if (mCore->mQueue.empty()) {
         return NO_BUFFER_AVAILABLE;
     }

     BufferQueueCore::Fifo::iterator front(mCore->mQueue.begin());

     // If expectedPresent is specified, we may not want to return a buffer yet.
     // If it's specified and there's more than one buffer queued, we may want
     // to drop a buffer.
     if (expectedPresent != 0) {
         const int MAX_REASONABLE_NSEC = 1000000000ULL; // 1 second

         // The 'expectedPresent' argument indicates when the buffer is expected
         // to be presented on-screen. If the buffer's desired present time is
         // earlier (less) than expectedPresent -- meaning it will be displayed
         // on time or possibly late if we show it as soon as possible -- we
         // acquire and return it. If we don't want to display it until after the
         // expectedPresent time, we return PRESENT_LATER without acquiring it.
         //
         // To be safe, we don't defer acquisition if expectedPresent is more
         // than one second in the future beyond the desired present time
         // (i.e., we'd be holding the buffer for a long time).
         //
         // NOTE: Code assumes monotonic time values from the system clock
         // are positive.

         // Start by checking to see if we can drop frames. We skip this check if
         // the timestamps are being auto-generated by Surface. If the app isn't
         // generating timestamps explicitly, it probably doesn't want frames to
         // be discarded based on them.
         while (mCore->mQueue.size() > 1 && !mCore->mQueue[0].mIsAutoTimestamp) {
             // If entry[1] is timely, drop entry[0] (and repeat). We apply an
             // additional criterion here: we only drop the earlier buffer if our
             // desiredPresent falls within +/- 1 second of the expected present.
             // Otherwise, bogus desiredPresent times (e.g., 0 or a small
             // relative timestamp), which normally mean "ignore the timestamp
             // and acquire immediately", would cause us to drop frames.
             //
             // We may want to add an additional criterion: don't drop the
             // earlier buffer if entry[1]'s fence hasn't signaled yet.
             const BufferItem& bufferItem(mCore->mQueue[1]);
             nsecs_t desiredPresent = bufferItem.mTimestamp;
             if (desiredPresent < expectedPresent - MAX_REASONABLE_NSEC ||
                     desiredPresent > expectedPresent) {
                 // This buffer is set to display in the near future, or
                 // desiredPresent is garbage. Either way we don't want to drop
                 // the previous buffer just to get this on the screen sooner.
                 BQ_LOGV("acquireBuffer: nodrop desire=%" PRId64 " expect=%"
                         PRId64 " (%" PRId64 ") now=%" PRId64,
                         desiredPresent, expectedPresent,
                         desiredPresent - expectedPresent,
                         systemTime(CLOCK_MONOTONIC));
                 break;
             }

             BQ_LOGV("acquireBuffer: drop desire=%" PRId64 " expect=%" PRId64
                     " size=%zu",
                     desiredPresent, expectedPresent, mCore->mQueue.size());
             if (mCore->stillTracking(front)) {
                 // Front buffer is still in mSlots, so mark the slot as free
                 mSlots[front->mSlot].mBufferState = BufferSlot::FREE;
             }
             mCore->mQueue.erase(front);
             front = mCore->mQueue.begin();
         }

         // See if the front buffer is due
         nsecs_t desiredPresent = front->mTimestamp;
         if (desiredPresent > expectedPresent &&
                 desiredPresent < expectedPresent + MAX_REASONABLE_NSEC) {
             BQ_LOGV("acquireBuffer: defer desire=%" PRId64 " expect=%" PRId64
                     " (%" PRId64 ") now=%" PRId64,
                     desiredPresent, expectedPresent,
                     desiredPresent - expectedPresent,
                     systemTime(CLOCK_MONOTONIC));
             return PRESENT_LATER;
         }

         BQ_LOGV("acquireBuffer: accept desire=%" PRId64 " expect=%" PRId64 " "
                 "(%" PRId64 ") now=%" PRId64, desiredPresent, expectedPresent,
                 desiredPresent - expectedPresent,
                 systemTime(CLOCK_MONOTONIC));
     }

     int slot = front->mSlot;
     *outBuffer = *front;
     ATRACE_BUFFER_INDEX(slot);

     BQ_LOGV("acquireBuffer: acquiring { slot=%d/%" PRIu64 " buffer=%p }",
             slot, front->mFrameNumber, front->mGraphicBuffer->handle);
     // If the front buffer is still being tracked, update its slot state
     if (mCore->stillTracking(front)) {
         mSlots[slot].mAcquireCalled = true;
         mSlots[slot].mNeedsCleanupOnRelease = false;
         mSlots[slot].mBufferState = BufferSlot::ACQUIRED;
         mSlots[slot].mFence = Fence::NO_FENCE;
     }

     // If the buffer has previously been acquired by the consumer, set
     // mGraphicBuffer to NULL to avoid unnecessarily remapping this buffer
     // on the consumer side
     if (outBuffer->mAcquireCalled) {
         outBuffer->mGraphicBuffer = NULL;
     }

     mCore->mQueue.erase(front);

     // We might have freed a slot while dropping old buffers, or the producer
     // may be blocked waiting for the number of buffers in the queue to
     // decrease.
     mCore->mDequeueCondition.broadcast();

     ATRACE_INT(mCore->mConsumerName.string(), mCore->mQueue.size());

     return NO_ERROR;
 }

 status_t BufferQueueConsumer::detachBuffer(int slot) {
     ATRACE_CALL();
     ATRACE_BUFFER_INDEX(slot);
     BQ_LOGV("detachBuffer(C): slot %d", slot);
     Mutex::Autolock lock(mCore->mMutex);

     if (mCore->mIsAbandoned) {
         BQ_LOGE("detachBuffer(C): BufferQueue has been abandoned");
         return NO_INIT;
     }

     if (slot < 0 || slot >= BufferQueueDefs::NUM_BUFFER_SLOTS) {
         BQ_LOGE("detachBuffer(C): slot index %d out of range [0, %d)",
                 slot, BufferQueueDefs::NUM_BUFFER_SLOTS);
         return BAD_VALUE;
     } else if (mSlots[slot].mBufferState != BufferSlot::ACQUIRED) {
         BQ_LOGE("detachBuffer(C): slot %d is not owned by the consumer "
                 "(state = %d)", slot, mSlots[slot].mBufferState);
         return BAD_VALUE;
     }

     mCore->freeBufferLocked(slot);
     mCore->mDequeueCondition.broadcast();

     return NO_ERROR;
 }

 status_t BufferQueueConsumer::attachBuffer(int* outSlot,
         const sp<android::GraphicBuffer>& buffer) {
     ATRACE_CALL();

     if (outSlot == NULL) {
         BQ_LOGE("attachBuffer(P): outSlot must not be NULL");
         return BAD_VALUE;
     } else if (buffer == NULL) {
         BQ_LOGE("attachBuffer(P): cannot attach NULL buffer");
         return BAD_VALUE;
     }

     Mutex::Autolock lock(mCore->mMutex);

     // Make sure we don't have too many acquired buffers and find a free slot
     // to put the buffer into (the oldest if there are multiple).
     int numAcquiredBuffers = 0;
     int found = BufferQueueCore::INVALID_BUFFER_SLOT;
     for (int s = 0; s < BufferQueueDefs::NUM_BUFFER_SLOTS; ++s) {
         if (mSlots[s].mBufferState == BufferSlot::ACQUIRED) {
             ++numAcquiredBuffers;
         } else if (mSlots[s].mBufferState == BufferSlot::FREE) {
             if (found == BufferQueueCore::INVALID_BUFFER_SLOT ||
                     mSlots[s].mFrameNumber < mSlots[found].mFrameNumber) {
                 found = s;
             }
         }
     }

     if (numAcquiredBuffers >= mCore->mMaxAcquiredBufferCount + 1) {
         BQ_LOGE("attachBuffer(P): max acquired buffer count reached: %d "
                 "(max %d)", numAcquiredBuffers,
                 mCore->mMaxAcquiredBufferCount);
         return INVALID_OPERATION;
     }
     if (found == BufferQueueCore::INVALID_BUFFER_SLOT) {
         BQ_LOGE("attachBuffer(P): could not find free buffer slot");
         return NO_MEMORY;
     }

     *outSlot = found;
     ATRACE_BUFFER_INDEX(*outSlot);
     BQ_LOGV("attachBuffer(C): returning slot %d", *outSlot);

     mSlots[*outSlot].mGraphicBuffer = buffer;
     mSlots[*outSlot].mBufferState = BufferSlot::ACQUIRED;
     mSlots[*outSlot].mAttachedByConsumer = true;
     mSlots[*outSlot].mNeedsCleanupOnRelease = false;
     mSlots[*outSlot].mFence = Fence::NO_FENCE;
     mSlots[*outSlot].mFrameNumber = 0;

     // mAcquireCalled tells BufferQueue that it doesn't need to send a valid
     // GraphicBuffer pointer on the next acquireBuffer call, which decreases
     // Binder traffic by not un/flattening the GraphicBuffer. However, it
     // requires that the consumer maintain a cached copy of the slot <--> buffer
     // mappings, which is why the consumer doesn't need the valid pointer on
     // acquire.
     //
     // The StreamSplitter is one of the primary users of the attach/detach
     // logic, and while it is running, all buffers it acquires are immediately
     // detached, and all buffers it eventually releases are ones that were
     // attached (as opposed to having been obtained from acquireBuffer), so it
     // doesn't make sense to maintain the slot/buffer mappings, which would
     // become invalid for every buffer during detach/attach. By setting this to
     // false, the valid GraphicBuffer pointer will always be sent with acquire
     // for attached buffers.
     mSlots[*outSlot].mAcquireCalled = false;

     return NO_ERROR;
 }

 status_t BufferQueueConsumer::releaseBuffer(int slot, uint64_t frameNumber,
         const sp<Fence>& releaseFence, EGLDisplay eglDisplay,
         EGLSyncKHR eglFence) {
     ATRACE_CALL();
     ATRACE_BUFFER_INDEX(slot);

     if (slot < 0 || slot >= BufferQueueDefs::NUM_BUFFER_SLOTS ||
             releaseFence == NULL) {
         return BAD_VALUE;
     }

     sp<IProducerListener> listener;
     { // Autolock scope
         Mutex::Autolock lock(mCore->mMutex);

         // If the frame number has changed because the buffer has been reallocated,
         // we can ignore this releaseBuffer for the old buffer
         if (frameNumber != mSlots[slot].mFrameNumber) {
             return STALE_BUFFER_SLOT;
         }

         // Make sure this buffer hasn't been queued while acquired by the consumer
         BufferQueueCore::Fifo::iterator current(mCore->mQueue.begin());
         while (current != mCore->mQueue.end()) {
             if (current->mSlot == slot) {
                 BQ_LOGE("releaseBuffer: buffer slot %d pending release is "
                         "currently queued", slot);
                 return BAD_VALUE;
             }
             ++current;
         }

         if (mSlots[slot].mBufferState == BufferSlot::ACQUIRED) {
             mSlots[slot].mEglDisplay = eglDisplay;
             mSlots[slot].mEglFence = eglFence;
             mSlots[slot].mFence = releaseFence;
             mSlots[slot].mBufferState = BufferSlot::FREE;
             listener = mCore->mConnectedProducerListener;
             BQ_LOGV("releaseBuffer: releasing slot %d", slot);
         } else if (mSlots[slot].mNeedsCleanupOnRelease) {
             BQ_LOGV("releaseBuffer: releasing a stale buffer slot %d "
                     "(state = %d)", slot, mSlots[slot].mBufferState);
             mSlots[slot].mNeedsCleanupOnRelease = false;
             return STALE_BUFFER_SLOT;
         } else {
             BQ_LOGV("releaseBuffer: attempted to release buffer slot %d "
                     "but its state was %d", slot, mSlots[slot].mBufferState);
             return BAD_VALUE;
         }

         mCore->mDequeueCondition.broadcast();
     } // Autolock scope

     // Call back without lock held
     if (listener != NULL) {
         listener->onBufferReleased();
     }

     return NO_ERROR;
 }

 status_t BufferQueueConsumer::connect(
         const sp<IConsumerListener>& consumerListener, bool controlledByApp) {
     ATRACE_CALL();

     if (consumerListener == NULL) {
         BQ_LOGE("connect(C): consumerListener may not be NULL");
         return BAD_VALUE;
     }

     BQ_LOGV("connect(C): controlledByApp=%s",
             controlledByApp ? "true" : "false");

     Mutex::Autolock lock(mCore->mMutex);

     if (mCore->mIsAbandoned) {
         BQ_LOGE("connect(C): BufferQueue has been abandoned");
         return NO_INIT;
     }

     mCore->mConsumerListener = consumerListener;
     mCore->mConsumerControlledByApp = controlledByApp;

     return NO_ERROR;
 }

 status_t BufferQueueConsumer::disconnect() {
     ATRACE_CALL();

     BQ_LOGV("disconnect(C)");

     Mutex::Autolock lock(mCore->mMutex);

     if (mCore->mConsumerListener == NULL) {
         BQ_LOGE("disconnect(C): no consumer is connected");
         return BAD_VALUE;
     }

     mCore->mIsAbandoned = true;
     mCore->mConsumerListener = NULL;
     mCore->mQueue.clear();
     mCore->freeAllBuffersLocked();
     mCore->mDequeueCondition.broadcast();
     return NO_ERROR;
 }

 status_t BufferQueueConsumer::getReleasedBuffers(uint64_t *outSlotMask) {
     ATRACE_CALL();

     if (outSlotMask == NULL) {
         BQ_LOGE("getReleasedBuffers: outSlotMask may not be NULL");
         return BAD_VALUE;
     }

     Mutex::Autolock lock(mCore->mMutex);

     if (mCore->mIsAbandoned) {
         BQ_LOGE("getReleasedBuffers: BufferQueue has been abandoned");
         return NO_INIT;
     }

     uint64_t mask = 0;
     for (int s = 0; s < BufferQueueDefs::NUM_BUFFER_SLOTS; ++s) {
         if (!mSlots[s].mAcquireCalled) {
             mask |= (1ULL << s);
         }
     }

     // Remove from the mask queued buffers for which acquire has been called,
     // since the consumer will not receive their buffer addresses and so must
     // retain their cached information
     BufferQueueCore::Fifo::iterator current(mCore->mQueue.begin());
     while (current != mCore->mQueue.end()) {
         if (current->mAcquireCalled) {
             mask &= ~(1ULL << current->mSlot);
         }
         ++current;
     }

     BQ_LOGV("getReleasedBuffers: returning mask %#" PRIx64, mask);
     *outSlotMask = mask;
     return NO_ERROR;
 }

 status_t BufferQueueConsumer::setDefaultBufferSize(uint32_t width,
         uint32_t height) {
     ATRACE_CALL();

     if (width == 0 || height == 0) {
         BQ_LOGV("setDefaultBufferSize: dimensions cannot be 0 (width=%u "
                 "height=%u)", width, height);
         return BAD_VALUE;
     }

     BQ_LOGV("setDefaultBufferSize: width=%u height=%u", width, height);

     Mutex::Autolock lock(mCore->mMutex);
     mCore->mDefaultWidth = width;
     mCore->mDefaultHeight = height;
     return NO_ERROR;
 }

 status_t BufferQueueConsumer::setDefaultMaxBufferCount(int bufferCount) {
     ATRACE_CALL();
     Mutex::Autolock lock(mCore->mMutex);
     return mCore->setDefaultMaxBufferCountLocked(bufferCount);
 }

 status_t BufferQueueConsumer::disableAsyncBuffer() {
     ATRACE_CALL();

     Mutex::Autolock lock(mCore->mMutex);

     if (mCore->mConsumerListener != NULL) {
         BQ_LOGE("disableAsyncBuffer: consumer already connected");
         return INVALID_OPERATION;
     }

     BQ_LOGV("disableAsyncBuffer");
     mCore->mUseAsyncBuffer = false;
     return NO_ERROR;
 }

 status_t BufferQueueConsumer::setMaxAcquiredBufferCount(
         int maxAcquiredBuffers) {
     ATRACE_CALL();

     if (maxAcquiredBuffers < 1 ||
             maxAcquiredBuffers > BufferQueueCore::MAX_MAX_ACQUIRED_BUFFERS) {
         BQ_LOGE("setMaxAcquiredBufferCount: invalid count %d",
                 maxAcquiredBuffers);
         return BAD_VALUE;
     }

     Mutex::Autolock lock(mCore->mMutex);

     if (mCore->mConnectedApi != BufferQueueCore::NO_CONNECTED_API) {
         BQ_LOGE("setMaxAcquiredBufferCount: producer is already connected");
         return INVALID_OPERATION;
     }

     BQ_LOGV("setMaxAcquiredBufferCount: %d", maxAcquiredBuffers);
     mCore->mMaxAcquiredBufferCount = maxAcquiredBuffers;
     return NO_ERROR;
 }

 void BufferQueueConsumer::setConsumerName(const String8& name) {
     ATRACE_CALL();
     BQ_LOGV("setConsumerName: '%s'", name.string());
     Mutex::Autolock lock(mCore->mMutex);
     mCore->mConsumerName = name;
     mConsumerName = name;
 }

 status_t BufferQueueConsumer::setDefaultBufferFormat(uint32_t defaultFormat) {
     ATRACE_CALL();
     BQ_LOGV("setDefaultBufferFormat: %u", defaultFormat);
     Mutex::Autolock lock(mCore->mMutex);
     mCore->mDefaultBufferFormat = defaultFormat;
     return NO_ERROR;
 }

 status_t BufferQueueConsumer::setConsumerUsageBits(uint32_t usage) {
     ATRACE_CALL();
     BQ_LOGV("setConsumerUsageBits: %#x", usage);
     Mutex::Autolock lock(mCore->mMutex);
     mCore->mConsumerUsageBits = usage;
     return NO_ERROR;
 }

 status_t BufferQueueConsumer::setTransformHint(uint32_t hint) {
     ATRACE_CALL();
     BQ_LOGV("setTransformHint: %#x", hint);
     Mutex::Autolock lock(mCore->mMutex);
     mCore->mTransformHint = hint;
     return NO_ERROR;
 }

 sp<NativeHandle> BufferQueueConsumer::getSidebandStream() const {
     return mCore->mSidebandStream;
 }

 void BufferQueueConsumer::dump(String8& result, const char* prefix) const {
     mCore->dump(result, prefix);
 }

 } // namespace android
	/*
	* Copyright 2014 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <inttypes.h>

	#define LOG_TAG "BufferQueueConsumer"
	#define ATRACE_TAG ATRACE_TAG_GRAPHICS
	//#define LOG_NDEBUG 0

	#include <gui/BufferItem.h>
	#include <gui/BufferQueueConsumer.h>
	#include <gui/BufferQueueCore.h>
	#include <gui/IConsumerListener.h>
	#include <gui/IProducerListener.h>

	namespace android {

	BufferQueueConsumer::BufferQueueConsumer(const sp<BufferQueueCore>& core) :
	mCore(core),
	mSlots(core->mSlots),
	mConsumerName() {}

	BufferQueueConsumer::~BufferQueueConsumer() {}

	status_t BufferQueueConsumer::acquireBuffer(BufferItem* outBuffer,
	nsecs_t expectedPresent) {
	ATRACE_CALL();
	Mutex::Autolock lock(mCore->mMutex);

	// Check that the consumer doesn't currently have the maximum number of
	// buffers acquired. We allow the max buffer count to be exceeded by one
	// buffer so that the consumer can successfully set up the newly acquired
	// buffer before releasing the old one.
	int numAcquiredBuffers = 0;
	for (int s = 0; s < BufferQueueDefs::NUM_BUFFER_SLOTS; ++s) {
	if (mSlots[s].mBufferState == BufferSlot::ACQUIRED) {
	++numAcquiredBuffers;
	}
	}
	if (numAcquiredBuffers >= mCore->mMaxAcquiredBufferCount + 1) {
	BQ_LOGE("acquireBuffer: max acquired buffer count reached: %d (max %d)",
	numAcquiredBuffers, mCore->mMaxAcquiredBufferCount);
	return INVALID_OPERATION;
	}

	// Check if the queue is empty.
	// In asynchronous mode the list is guaranteed to be one buffer deep,
	// while in synchronous mode we use the oldest buffer.
	if (mCore->mQueue.empty()) {
	return NO_BUFFER_AVAILABLE;
	}

	BufferQueueCore::Fifo::iterator front(mCore->mQueue.begin());

	// If expectedPresent is specified, we may not want to return a buffer yet.
	// If it's specified and there's more than one buffer queued, we may want
	// to drop a buffer.
	if (expectedPresent != 0) {
	const int MAX_REASONABLE_NSEC = 1000000000ULL; // 1 second

	// The 'expectedPresent' argument indicates when the buffer is expected
	// to be presented on-screen. If the buffer's desired present time is
	// earlier (less) than expectedPresent -- meaning it will be displayed
	// on time or possibly late if we show it as soon as possible -- we
	// acquire and return it. If we don't want to display it until after the
	// expectedPresent time, we return PRESENT_LATER without acquiring it.
	//
	// To be safe, we don't defer acquisition if expectedPresent is more
	// than one second in the future beyond the desired present time
	// (i.e., we'd be holding the buffer for a long time).
	//
	// NOTE: Code assumes monotonic time values from the system clock
	// are positive.

	// Start by checking to see if we can drop frames. We skip this check if
	// the timestamps are being auto-generated by Surface. If the app isn't
	// generating timestamps explicitly, it probably doesn't want frames to
	// be discarded based on them.
	while (mCore->mQueue.size() > 1 && !mCore->mQueue[0].mIsAutoTimestamp) {
	// If entry[1] is timely, drop entry[0] (and repeat). We apply an
	// additional criterion here: we only drop the earlier buffer if our
	// desiredPresent falls within +/- 1 second of the expected present.
	// Otherwise, bogus desiredPresent times (e.g., 0 or a small
	// relative timestamp), which normally mean "ignore the timestamp
	// and acquire immediately", would cause us to drop frames.
	//
	// We may want to add an additional criterion: don't drop the
	// earlier buffer if entry[1]'s fence hasn't signaled yet.
	const BufferItem& bufferItem(mCore->mQueue[1]);
	nsecs_t desiredPresent = bufferItem.mTimestamp;
	if (desiredPresent < expectedPresent - MAX_REASONABLE_NSEC \|\|
	desiredPresent > expectedPresent) {
	// This buffer is set to display in the near future, or
	// desiredPresent is garbage. Either way we don't want to drop
	// the previous buffer just to get this on the screen sooner.
	BQ_LOGV("acquireBuffer: nodrop desire=%" PRId64 " expect=%"
	PRId64 " (%" PRId64 ") now=%" PRId64,
	desiredPresent, expectedPresent,
	desiredPresent - expectedPresent,
	systemTime(CLOCK_MONOTONIC));
	break;
	}

	BQ_LOGV("acquireBuffer: drop desire=%" PRId64 " expect=%" PRId64
	" size=%zu",
	desiredPresent, expectedPresent, mCore->mQueue.size());
	if (mCore->stillTracking(front)) {
	// Front buffer is still in mSlots, so mark the slot as free
	mSlots[front->mSlot].mBufferState = BufferSlot::FREE;
	}
	mCore->mQueue.erase(front);
	front = mCore->mQueue.begin();
	}

	// See if the front buffer is due
	nsecs_t desiredPresent = front->mTimestamp;
	if (desiredPresent > expectedPresent &&
	desiredPresent < expectedPresent + MAX_REASONABLE_NSEC) {
	BQ_LOGV("acquireBuffer: defer desire=%" PRId64 " expect=%" PRId64
	" (%" PRId64 ") now=%" PRId64,
	desiredPresent, expectedPresent,
	desiredPresent - expectedPresent,
	systemTime(CLOCK_MONOTONIC));
	return PRESENT_LATER;
	}

	BQ_LOGV("acquireBuffer: accept desire=%" PRId64 " expect=%" PRId64 " "
	"(%" PRId64 ") now=%" PRId64, desiredPresent, expectedPresent,
	desiredPresent - expectedPresent,
	systemTime(CLOCK_MONOTONIC));
	}

	int slot = front->mSlot;
	outBuffer = front;
	ATRACE_BUFFER_INDEX(slot);

	BQ_LOGV("acquireBuffer: acquiring { slot=%d/%" PRIu64 " buffer=%p }",
	slot, front->mFrameNumber, front->mGraphicBuffer->handle);
	// If the front buffer is still being tracked, update its slot state
	if (mCore->stillTracking(front)) {
	mSlots[slot].mAcquireCalled = true;
	mSlots[slot].mNeedsCleanupOnRelease = false;
	mSlots[slot].mBufferState = BufferSlot::ACQUIRED;
	mSlots[slot].mFence = Fence::NO_FENCE;
	}

	// If the buffer has previously been acquired by the consumer, set
	// mGraphicBuffer to NULL to avoid unnecessarily remapping this buffer
	// on the consumer side
	if (outBuffer->mAcquireCalled) {
	outBuffer->mGraphicBuffer = NULL;
	}

	mCore->mQueue.erase(front);

	// We might have freed a slot while dropping old buffers, or the producer
	// may be blocked waiting for the number of buffers in the queue to
	// decrease.
	mCore->mDequeueCondition.broadcast();

	ATRACE_INT(mCore->mConsumerName.string(), mCore->mQueue.size());

	return NO_ERROR;
	}

	status_t BufferQueueConsumer::detachBuffer(int slot) {
	ATRACE_CALL();
	ATRACE_BUFFER_INDEX(slot);
	BQ_LOGV("detachBuffer(C): slot %d", slot);
	Mutex::Autolock lock(mCore->mMutex);

	if (mCore->mIsAbandoned) {
	BQ_LOGE("detachBuffer(C): BufferQueue has been abandoned");
	return NO_INIT;
	}

	if (slot < 0 \|\| slot >= BufferQueueDefs::NUM_BUFFER_SLOTS) {
	BQ_LOGE("detachBuffer(C): slot index %d out of range [0, %d)",
	slot, BufferQueueDefs::NUM_BUFFER_SLOTS);
	return BAD_VALUE;
	} else if (mSlots[slot].mBufferState != BufferSlot::ACQUIRED) {
	BQ_LOGE("detachBuffer(C): slot %d is not owned by the consumer "
	"(state = %d)", slot, mSlots[slot].mBufferState);
	return BAD_VALUE;
	}

	mCore->freeBufferLocked(slot);
	mCore->mDequeueCondition.broadcast();

	return NO_ERROR;
	}

	status_t BufferQueueConsumer::attachBuffer(int* outSlot,
	const sp<android::GraphicBuffer>& buffer) {
	ATRACE_CALL();

	if (outSlot == NULL) {
	BQ_LOGE("attachBuffer(P): outSlot must not be NULL");
	return BAD_VALUE;
	} else if (buffer == NULL) {
	BQ_LOGE("attachBuffer(P): cannot attach NULL buffer");
	return BAD_VALUE;
	}

	Mutex::Autolock lock(mCore->mMutex);

	// Make sure we don't have too many acquired buffers and find a free slot
	// to put the buffer into (the oldest if there are multiple).
	int numAcquiredBuffers = 0;
	int found = BufferQueueCore::INVALID_BUFFER_SLOT;
	for (int s = 0; s < BufferQueueDefs::NUM_BUFFER_SLOTS; ++s) {
	if (mSlots[s].mBufferState == BufferSlot::ACQUIRED) {
	++numAcquiredBuffers;
	} else if (mSlots[s].mBufferState == BufferSlot::FREE) {
	if (found == BufferQueueCore::INVALID_BUFFER_SLOT \|\|
	mSlots[s].mFrameNumber < mSlots[found].mFrameNumber) {
	found = s;
	}
	}
	}

	if (numAcquiredBuffers >= mCore->mMaxAcquiredBufferCount + 1) {
	BQ_LOGE("attachBuffer(P): max acquired buffer count reached: %d "
	"(max %d)", numAcquiredBuffers,
	mCore->mMaxAcquiredBufferCount);
	return INVALID_OPERATION;
	}
	if (found == BufferQueueCore::INVALID_BUFFER_SLOT) {
	BQ_LOGE("attachBuffer(P): could not find free buffer slot");
	return NO_MEMORY;
	}

	*outSlot = found;
	ATRACE_BUFFER_INDEX(*outSlot);
	BQ_LOGV("attachBuffer(C): returning slot %d", *outSlot);

	mSlots[*outSlot].mGraphicBuffer = buffer;
	mSlots[*outSlot].mBufferState = BufferSlot::ACQUIRED;
	mSlots[*outSlot].mAttachedByConsumer = true;
	mSlots[*outSlot].mNeedsCleanupOnRelease = false;
	mSlots[*outSlot].mFence = Fence::NO_FENCE;
	mSlots[*outSlot].mFrameNumber = 0;

	// mAcquireCalled tells BufferQueue that it doesn't need to send a valid
	// GraphicBuffer pointer on the next acquireBuffer call, which decreases
	// Binder traffic by not un/flattening the GraphicBuffer. However, it
	// requires that the consumer maintain a cached copy of the slot <--> buffer
	// mappings, which is why the consumer doesn't need the valid pointer on
	// acquire.
	//
	// The StreamSplitter is one of the primary users of the attach/detach
	// logic, and while it is running, all buffers it acquires are immediately
	// detached, and all buffers it eventually releases are ones that were
	// attached (as opposed to having been obtained from acquireBuffer), so it
	// doesn't make sense to maintain the slot/buffer mappings, which would
	// become invalid for every buffer during detach/attach. By setting this to
	// false, the valid GraphicBuffer pointer will always be sent with acquire
	// for attached buffers.
	mSlots[*outSlot].mAcquireCalled = false;

	return NO_ERROR;
	}

	status_t BufferQueueConsumer::releaseBuffer(int slot, uint64_t frameNumber,
	const sp<Fence>& releaseFence, EGLDisplay eglDisplay,
	EGLSyncKHR eglFence) {
	ATRACE_CALL();
	ATRACE_BUFFER_INDEX(slot);

	if (slot < 0 \|\| slot >= BufferQueueDefs::NUM_BUFFER_SLOTS \|\|
	releaseFence == NULL) {
	return BAD_VALUE;
	}

	sp<IProducerListener> listener;
	{ // Autolock scope
	Mutex::Autolock lock(mCore->mMutex);

	// If the frame number has changed because the buffer has been reallocated,
	// we can ignore this releaseBuffer for the old buffer
	if (frameNumber != mSlots[slot].mFrameNumber) {
	return STALE_BUFFER_SLOT;
	}

	// Make sure this buffer hasn't been queued while acquired by the consumer
	BufferQueueCore::Fifo::iterator current(mCore->mQueue.begin());
	while (current != mCore->mQueue.end()) {
	if (current->mSlot == slot) {
	BQ_LOGE("releaseBuffer: buffer slot %d pending release is "
	"currently queued", slot);
	return BAD_VALUE;
	}
	++current;
	}

	if (mSlots[slot].mBufferState == BufferSlot::ACQUIRED) {
	mSlots[slot].mEglDisplay = eglDisplay;
	mSlots[slot].mEglFence = eglFence;
	mSlots[slot].mFence = releaseFence;
	mSlots[slot].mBufferState = BufferSlot::FREE;
	listener = mCore->mConnectedProducerListener;
	BQ_LOGV("releaseBuffer: releasing slot %d", slot);
	} else if (mSlots[slot].mNeedsCleanupOnRelease) {
	BQ_LOGV("releaseBuffer: releasing a stale buffer slot %d "
	"(state = %d)", slot, mSlots[slot].mBufferState);
	mSlots[slot].mNeedsCleanupOnRelease = false;
	return STALE_BUFFER_SLOT;
	} else {
	BQ_LOGV("releaseBuffer: attempted to release buffer slot %d "
	"but its state was %d", slot, mSlots[slot].mBufferState);
	return BAD_VALUE;
	}

	mCore->mDequeueCondition.broadcast();
	} // Autolock scope

	// Call back without lock held
	if (listener != NULL) {
	listener->onBufferReleased();
	}

	return NO_ERROR;
	}

	status_t BufferQueueConsumer::connect(
	const sp<IConsumerListener>& consumerListener, bool controlledByApp) {
	ATRACE_CALL();

	if (consumerListener == NULL) {
	BQ_LOGE("connect(C): consumerListener may not be NULL");
	return BAD_VALUE;
	}

	BQ_LOGV("connect(C): controlledByApp=%s",
	controlledByApp ? "true" : "false");

	Mutex::Autolock lock(mCore->mMutex);

	if (mCore->mIsAbandoned) {
	BQ_LOGE("connect(C): BufferQueue has been abandoned");
	return NO_INIT;
	}

	mCore->mConsumerListener = consumerListener;
	mCore->mConsumerControlledByApp = controlledByApp;

	return NO_ERROR;
	}

	status_t BufferQueueConsumer::disconnect() {
	ATRACE_CALL();

	BQ_LOGV("disconnect(C)");

	Mutex::Autolock lock(mCore->mMutex);

	if (mCore->mConsumerListener == NULL) {
	BQ_LOGE("disconnect(C): no consumer is connected");
	return BAD_VALUE;
	}

	mCore->mIsAbandoned = true;
	mCore->mConsumerListener = NULL;
	mCore->mQueue.clear();
	mCore->freeAllBuffersLocked();
	mCore->mDequeueCondition.broadcast();
	return NO_ERROR;
	}

	status_t BufferQueueConsumer::getReleasedBuffers(uint64_t *outSlotMask) {
	ATRACE_CALL();

	if (outSlotMask == NULL) {
	BQ_LOGE("getReleasedBuffers: outSlotMask may not be NULL");
	return BAD_VALUE;
	}

	Mutex::Autolock lock(mCore->mMutex);

	if (mCore->mIsAbandoned) {
	BQ_LOGE("getReleasedBuffers: BufferQueue has been abandoned");
	return NO_INIT;
	}

	uint64_t mask = 0;
	for (int s = 0; s < BufferQueueDefs::NUM_BUFFER_SLOTS; ++s) {
	if (!mSlots[s].mAcquireCalled) {
	mask \|= (1ULL << s);
	}
	}

	// Remove from the mask queued buffers for which acquire has been called,
	// since the consumer will not receive their buffer addresses and so must
	// retain their cached information
	BufferQueueCore::Fifo::iterator current(mCore->mQueue.begin());
	while (current != mCore->mQueue.end()) {
	if (current->mAcquireCalled) {
	mask &= ~(1ULL << current->mSlot);
	}
	++current;
	}

	BQ_LOGV("getReleasedBuffers: returning mask %#" PRIx64, mask);
	*outSlotMask = mask;
	return NO_ERROR;
	}

	status_t BufferQueueConsumer::setDefaultBufferSize(uint32_t width,
	uint32_t height) {
	ATRACE_CALL();

	if (width == 0 \|\| height == 0) {
	BQ_LOGV("setDefaultBufferSize: dimensions cannot be 0 (width=%u "
	"height=%u)", width, height);
	return BAD_VALUE;
	}

	BQ_LOGV("setDefaultBufferSize: width=%u height=%u", width, height);

	Mutex::Autolock lock(mCore->mMutex);
	mCore->mDefaultWidth = width;
	mCore->mDefaultHeight = height;
	return NO_ERROR;
	}

	status_t BufferQueueConsumer::setDefaultMaxBufferCount(int bufferCount) {
	ATRACE_CALL();
	Mutex::Autolock lock(mCore->mMutex);
	return mCore->setDefaultMaxBufferCountLocked(bufferCount);
	}

	status_t BufferQueueConsumer::disableAsyncBuffer() {
	ATRACE_CALL();

	Mutex::Autolock lock(mCore->mMutex);

	if (mCore->mConsumerListener != NULL) {
	BQ_LOGE("disableAsyncBuffer: consumer already connected");
	return INVALID_OPERATION;
	}

	BQ_LOGV("disableAsyncBuffer");
	mCore->mUseAsyncBuffer = false;
	return NO_ERROR;
	}

	status_t BufferQueueConsumer::setMaxAcquiredBufferCount(
	int maxAcquiredBuffers) {
	ATRACE_CALL();

	if (maxAcquiredBuffers < 1 \|\|
	maxAcquiredBuffers > BufferQueueCore::MAX_MAX_ACQUIRED_BUFFERS) {
	BQ_LOGE("setMaxAcquiredBufferCount: invalid count %d",
	maxAcquiredBuffers);
	return BAD_VALUE;
	}

	Mutex::Autolock lock(mCore->mMutex);

	if (mCore->mConnectedApi != BufferQueueCore::NO_CONNECTED_API) {
	BQ_LOGE("setMaxAcquiredBufferCount: producer is already connected");
	return INVALID_OPERATION;
	}

	BQ_LOGV("setMaxAcquiredBufferCount: %d", maxAcquiredBuffers);
	mCore->mMaxAcquiredBufferCount = maxAcquiredBuffers;
	return NO_ERROR;
	}

	void BufferQueueConsumer::setConsumerName(const String8& name) {
	ATRACE_CALL();
	BQ_LOGV("setConsumerName: '%s'", name.string());
	Mutex::Autolock lock(mCore->mMutex);
	mCore->mConsumerName = name;
	mConsumerName = name;
	}

	status_t BufferQueueConsumer::setDefaultBufferFormat(uint32_t defaultFormat) {
	ATRACE_CALL();
	BQ_LOGV("setDefaultBufferFormat: %u", defaultFormat);
	Mutex::Autolock lock(mCore->mMutex);
	mCore->mDefaultBufferFormat = defaultFormat;
	return NO_ERROR;
	}

	status_t BufferQueueConsumer::setConsumerUsageBits(uint32_t usage) {
	ATRACE_CALL();
	BQ_LOGV("setConsumerUsageBits: %#x", usage);
	Mutex::Autolock lock(mCore->mMutex);
	mCore->mConsumerUsageBits = usage;
	return NO_ERROR;
	}

	status_t BufferQueueConsumer::setTransformHint(uint32_t hint) {
	ATRACE_CALL();
	BQ_LOGV("setTransformHint: %#x", hint);
	Mutex::Autolock lock(mCore->mMutex);
	mCore->mTransformHint = hint;
	return NO_ERROR;
	}

	sp<NativeHandle> BufferQueueConsumer::getSidebandStream() const {
	return mCore->mSidebandStream;
	}

	void BufferQueueConsumer::dump(String8& result, const char* prefix) const {
	mCore->dump(result, prefix);
	}

	} // namespace android