status_t BufferQueueConsumer::acquireBuffer(BufferItem* outBuffer,
nsecs_t expectedPresent, uint64_t maxFrameNumber) {
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;
+ int numDroppedBuffers = 0;
+ sp<IProducerListener> listener;
+ {
+ 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;
}
- }
- 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;
- }
+ // 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) {
- const BufferItem& bufferItem(mCore->mQueue[1]);
-
- // If dropping entry[0] would leave us with a buffer that the
- // consumer is not yet ready for, don't drop it.
- if (maxFrameNumber && bufferItem.mFrameNumber > maxFrameNumber) {
- break;
- }
+ 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
- // 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.
+ // 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.
//
- // We may want to add an additional criterion: don't drop the
- // earlier buffer if entry[1]'s fence hasn't signaled yet.
- 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;
+ // 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) {
+ const BufferItem& bufferItem(mCore->mQueue[1]);
+
+ // If dropping entry[0] would leave us with a buffer that the
+ // consumer is not yet ready for, don't drop it.
+ if (maxFrameNumber && bufferItem.mFrameNumber > maxFrameNumber) {
+ break;
+ }
+
+ // 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.
+ 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->mFreeBuffers.push_back(front->mSlot);
+ listener = mCore->mConnectedProducerListener;
+ ++numDroppedBuffers;
+ }
+ mCore->mQueue.erase(front);
+ front = mCore->mQueue.begin();
}
- 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->mFreeBuffers.push_back(front->mSlot);
+ // See if the front buffer is ready to be acquired
+ nsecs_t desiredPresent = front->mTimestamp;
+ bool bufferIsDue = desiredPresent <= expectedPresent ||
+ desiredPresent > expectedPresent + MAX_REASONABLE_NSEC;
+ bool consumerIsReady = maxFrameNumber > 0 ?
+ front->mFrameNumber <= maxFrameNumber : true;
+ if (!bufferIsDue || !consumerIsReady) {
+ BQ_LOGV("acquireBuffer: defer desire=%" PRId64 " expect=%" PRId64
+ " (%" PRId64 ") now=%" PRId64 " frame=%" PRIu64
+ " consumer=%" PRIu64,
+ desiredPresent, expectedPresent,
+ desiredPresent - expectedPresent,
+ systemTime(CLOCK_MONOTONIC),
+ front->mFrameNumber, maxFrameNumber);
+ return PRESENT_LATER;
}
- mCore->mQueue.erase(front);
- front = mCore->mQueue.begin();
- }
- // See if the front buffer is ready to be acquired
- nsecs_t desiredPresent = front->mTimestamp;
- bool bufferIsDue = desiredPresent <= expectedPresent ||
- desiredPresent > expectedPresent + MAX_REASONABLE_NSEC;
- bool consumerIsReady = maxFrameNumber > 0 ?
- front->mFrameNumber <= maxFrameNumber : true;
- if (!bufferIsDue || !consumerIsReady) {
- BQ_LOGV("acquireBuffer: defer desire=%" PRId64 " expect=%" PRId64
- " (%" PRId64 ") now=%" PRId64 " frame=%" PRIu64
- " consumer=%" PRIu64,
- desiredPresent, expectedPresent,
+ BQ_LOGV("acquireBuffer: accept desire=%" PRId64 " expect=%" PRId64 " "
+ "(%" PRId64 ") now=%" PRId64, desiredPresent, expectedPresent,
desiredPresent - expectedPresent,
- systemTime(CLOCK_MONOTONIC),
- front->mFrameNumber, maxFrameNumber);
- return PRESENT_LATER;
+ systemTime(CLOCK_MONOTONIC));
}
- 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);
- 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;
+ }
- 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;
+ }
- // 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);
- 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();
- // 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());
- ATRACE_INT(mCore->mConsumerName.string(), mCore->mQueue.size());
+ mCore->validateConsistencyLocked();
+ }
- mCore->validateConsistencyLocked();
+ if (listener != NULL) {
+ for (int i = 0; i < numDroppedBuffers; ++i) {
+ listener->onBufferReleased();
+ }
+ }
return NO_ERROR;
}
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