2 * Copyright (C) 2012 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 #ifndef ANDROID_GUI_BUFFERQUEUE_H
18 #define ANDROID_GUI_BUFFERQUEUE_H
21 #include <EGL/eglext.h>
23 #include <gui/IGraphicBufferAlloc.h>
24 #include <gui/IGraphicBufferProducer.h>
27 #include <ui/GraphicBuffer.h>
29 #include <utils/String8.h>
30 #include <utils/Vector.h>
31 #include <utils/threads.h>
34 // ----------------------------------------------------------------------------
36 class BufferQueue : public BnGraphicBufferProducer {
38 enum { MIN_UNDEQUEUED_BUFFERS = 2 };
39 enum { NUM_BUFFER_SLOTS = 32 };
40 enum { NO_CONNECTED_API = 0 };
41 enum { INVALID_BUFFER_SLOT = -1 };
42 enum { STALE_BUFFER_SLOT = 1, NO_BUFFER_AVAILABLE };
44 // When in async mode we reserve two slots in order to guarantee that the
45 // producer and consumer can run asynchronously.
46 enum { MAX_MAX_ACQUIRED_BUFFERS = NUM_BUFFER_SLOTS - 2 };
48 // ConsumerListener is the interface through which the BufferQueue notifies
49 // the consumer of events that the consumer may wish to react to. Because
50 // the consumer will generally have a mutex that is locked during calls from
51 // teh consumer to the BufferQueue, these calls from the BufferQueue to the
52 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked.
53 struct ConsumerListener : public virtual RefBase {
54 // onFrameAvailable is called from queueBuffer each time an additional
55 // frame becomes available for consumption. This means that frames that
56 // are queued while in asynchronous mode only trigger the callback if no
57 // previous frames are pending. Frames queued while in synchronous mode
58 // always trigger the callback.
60 // This is called without any lock held and can be called concurrently
61 // by multiple threads.
62 virtual void onFrameAvailable() = 0;
64 // onBuffersReleased is called to notify the buffer consumer that the
65 // BufferQueue has released its references to one or more GraphicBuffers
66 // contained in its slots. The buffer consumer should then call
67 // BufferQueue::getReleasedBuffers to retrieve the list of buffers
69 // This is called without any lock held and can be called concurrently
70 // by multiple threads.
71 virtual void onBuffersReleased() = 0;
74 // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak
75 // reference to the actual consumer object. It forwards all calls to that
76 // consumer object so long as it exists.
78 // This class exists to avoid having a circular reference between the
79 // BufferQueue object and the consumer object. The reason this can't be a weak
80 // reference in the BufferQueue class is because we're planning to expose the
81 // consumer side of a BufferQueue as a binder interface, which doesn't support
83 class ProxyConsumerListener : public BufferQueue::ConsumerListener {
86 ProxyConsumerListener(const wp<BufferQueue::ConsumerListener>& consumerListener);
87 virtual ~ProxyConsumerListener();
88 virtual void onFrameAvailable();
89 virtual void onBuffersReleased();
93 // mConsumerListener is a weak reference to the ConsumerListener. This is
94 // the raison d'etre of ProxyConsumerListener.
95 wp<BufferQueue::ConsumerListener> mConsumerListener;
99 // BufferQueue manages a pool of gralloc memory slots to be used by
100 // producers and consumers. allowSynchronousMode specifies whether or not
101 // synchronous mode can be enabled by the producer. allocator is used to
102 // allocate all the needed gralloc buffers.
103 BufferQueue(bool allowSynchronousMode = true,
104 const sp<IGraphicBufferAlloc>& allocator = NULL);
105 virtual ~BufferQueue();
107 virtual int query(int what, int* value);
109 // setBufferCount updates the number of available buffer slots. After
110 // calling this all buffer slots are both unallocated and owned by the
111 // BufferQueue object (i.e. they are not owned by the client).
112 virtual status_t setBufferCount(int bufferCount);
114 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf);
116 // dequeueBuffer gets the next buffer slot index for the client to use. If a
117 // buffer slot is available then that slot index is written to the location
118 // pointed to by the buf argument and a status of OK is returned. If no
119 // slot is available then a status of -EBUSY is returned and buf is
122 // The fence parameter will be updated to hold the fence associated with
123 // the buffer. The contents of the buffer must not be overwritten until the
124 // fence signals. If the fence is NULL, the buffer may be written
127 // The width and height parameters must be no greater than the minimum of
128 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
129 // An error due to invalid dimensions might not be reported until
130 // updateTexImage() is called.
131 virtual status_t dequeueBuffer(int *buf, sp<Fence>* fence,
132 uint32_t width, uint32_t height, uint32_t format, uint32_t usage);
134 // queueBuffer returns a filled buffer to the BufferQueue. In addition, a
135 // timestamp must be provided for the buffer. The timestamp is in
136 // nanoseconds, and must be monotonically increasing. Its other semantics
137 // (zero point, etc) are client-dependent and should be documented by the
139 virtual status_t queueBuffer(int buf,
140 const QueueBufferInput& input, QueueBufferOutput* output);
142 virtual void cancelBuffer(int buf, const sp<Fence>& fence);
144 // setSynchronousMode set whether dequeueBuffer is synchronous or
145 // asynchronous. In synchronous mode, dequeueBuffer blocks until
146 // a buffer is available, the currently bound buffer can be dequeued and
147 // queued buffers will be retired in order.
148 // The default mode is asynchronous.
149 virtual status_t setSynchronousMode(bool enabled);
151 // connect attempts to connect a producer client API to the BufferQueue.
152 // This must be called before any other IGraphicBufferProducer methods are called
153 // except for getAllocator.
155 // This method will fail if the connect was previously called on the
156 // BufferQueue and no corresponding disconnect call was made.
157 virtual status_t connect(int api, QueueBufferOutput* output);
159 // disconnect attempts to disconnect a producer client API from the
160 // BufferQueue. Calling this method will cause any subsequent calls to other
161 // IGraphicBufferProducer methods to fail except for getAllocator and connect.
162 // Successfully calling connect after this will allow the other methods to
165 // This method will fail if the the BufferQueue is not currently
166 // connected to the specified client API.
167 virtual status_t disconnect(int api);
169 // dump our state in a String
170 virtual void dump(String8& result) const;
171 virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const;
173 // public facing structure for BufferSlot
179 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE),
182 mBuf(INVALID_BUFFER_SLOT) {
185 // mGraphicBuffer points to the buffer allocated for this slot, or is NULL
186 // if the buffer in this slot has been acquired in the past (see
187 // BufferSlot.mAcquireCalled).
188 sp<GraphicBuffer> mGraphicBuffer;
190 // mCrop is the current crop rectangle for this buffer slot.
193 // mTransform is the current transform flags for this buffer slot.
196 // mScalingMode is the current scaling mode for this buffer slot.
197 uint32_t mScalingMode;
199 // mTimestamp is the current timestamp for this buffer slot. This gets
200 // to set by queueBuffer each time this slot is queued.
203 // mFrameNumber is the number of the queued frame for this slot.
204 uint64_t mFrameNumber;
206 // mBuf is the slot index of this buffer
209 // mFence is a fence that will signal when the buffer is idle.
213 // The following public functions is the consumer facing interface
215 // acquireBuffer attempts to acquire ownership of the next pending buffer in
216 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a
217 // buffer is successfully acquired, the information about the buffer is
218 // returned in BufferItem. If the buffer returned had previously been
219 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to
220 // NULL and it is assumed that the consumer still holds a reference to the
222 status_t acquireBuffer(BufferItem *buffer);
224 // releaseBuffer releases a buffer slot from the consumer back to the
225 // BufferQueue pending a fence sync.
227 // If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free
228 // any references to the just-released buffer that it might have, as if it
229 // had received a onBuffersReleased() call with a mask set for the released
232 // Note that the dependencies on EGL will be removed once we switch to using
233 // the Android HW Sync HAL.
234 status_t releaseBuffer(int buf, EGLDisplay display, EGLSyncKHR fence,
235 const sp<Fence>& releaseFence);
237 // consumerConnect connects a consumer to the BufferQueue. Only one
238 // consumer may be connected, and when that consumer disconnects the
239 // BufferQueue is placed into the "abandoned" state, causing most
240 // interactions with the BufferQueue by the producer to fail.
241 status_t consumerConnect(const sp<ConsumerListener>& consumer);
243 // consumerDisconnect disconnects a consumer from the BufferQueue. All
244 // buffers will be freed and the BufferQueue is placed in the "abandoned"
245 // state, causing most interactions with the BufferQueue by the producer to
247 status_t consumerDisconnect();
249 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask
250 // indicating which buffer slots the have been released by the BufferQueue
251 // but have not yet been released by the consumer.
252 status_t getReleasedBuffers(uint32_t* slotMask);
254 // setDefaultBufferSize is used to set the size of buffers returned by
255 // requestBuffers when a with and height of zero is requested.
256 status_t setDefaultBufferSize(uint32_t w, uint32_t h);
258 // setDefaultBufferCount set the buffer count. If the client has requested
259 // a buffer count using setBufferCount, the server-buffer count will
260 // take effect once the client sets the count back to zero.
261 status_t setDefaultMaxBufferCount(int bufferCount);
263 // setMaxAcquiredBufferCount sets the maximum number of buffers that can
264 // be acquired by the consumer at one time. This call will fail if a
265 // producer is connected to the BufferQueue.
266 status_t setMaxAcquiredBufferCount(int maxAcquiredBuffers);
268 // isSynchronousMode returns whether the BufferQueue is currently in
270 bool isSynchronousMode() const;
272 // setConsumerName sets the name used in logging
273 void setConsumerName(const String8& name);
275 // setDefaultBufferFormat allows the BufferQueue to create
276 // GraphicBuffers of a defaultFormat if no format is specified
278 status_t setDefaultBufferFormat(uint32_t defaultFormat);
280 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer
281 status_t setConsumerUsageBits(uint32_t usage);
283 // setTransformHint bakes in rotation to buffers so overlays can be used
284 status_t setTransformHint(uint32_t hint);
287 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage)
288 // for the given slot.
289 void freeBufferLocked(int index);
291 // freeAllBuffersLocked frees the resources (both GraphicBuffer and
292 // EGLImage) for all slots.
293 void freeAllBuffersLocked();
295 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer
296 // and EGLImage) for all slots except the head of mQueue
297 void freeAllBuffersExceptHeadLocked();
299 // drainQueueLocked drains the buffer queue if we're in synchronous mode
300 // returns immediately otherwise. It returns NO_INIT if the BufferQueue
301 // became abandoned or disconnected during this call.
302 status_t drainQueueLocked();
304 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in
305 // synchronous mode and free all buffers. In asynchronous mode, all buffers
306 // are freed except the current buffer.
307 status_t drainQueueAndFreeBuffersLocked();
309 // setDefaultMaxBufferCountLocked sets the maximum number of buffer slots
310 // that will be used if the producer does not override the buffer slot
312 status_t setDefaultMaxBufferCountLocked(int count);
314 // getMinBufferCountLocked returns the minimum number of buffers allowed
315 // given the current BufferQueue state.
316 int getMinMaxBufferCountLocked() const;
318 // getMinUndequeuedBufferCountLocked returns the minimum number of buffers
319 // that must remain in a state other than DEQUEUED.
320 int getMinUndequeuedBufferCountLocked() const;
322 // getMaxBufferCountLocked returns the maximum number of buffers that can
323 // be allocated at once. This value depends upon the following member
327 // mMaxAcquiredBufferCount
328 // mDefaultMaxBufferCount
329 // mOverrideMaxBufferCount
331 // Any time one of these member variables is changed while a producer is
332 // connected, mDequeueCondition must be broadcast.
333 int getMaxBufferCountLocked() const;
338 : mEglDisplay(EGL_NO_DISPLAY),
339 mBufferState(BufferSlot::FREE),
340 mRequestBufferCalled(false),
342 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE),
345 mEglFence(EGL_NO_SYNC_KHR),
346 mAcquireCalled(false),
347 mNeedsCleanupOnRelease(false) {
351 // mGraphicBuffer points to the buffer allocated for this slot or is NULL
352 // if no buffer has been allocated.
353 sp<GraphicBuffer> mGraphicBuffer;
355 // mEglDisplay is the EGLDisplay used to create mEglImage.
356 EGLDisplay mEglDisplay;
358 // BufferState represents the different states in which a buffer slot
361 // FREE indicates that the buffer is not currently being used and
362 // will not be used in the future until it gets dequeued and
363 // subsequently queued by the client.
364 // aka "owned by BufferQueue, ready to be dequeued"
367 // DEQUEUED indicates that the buffer has been dequeued by the
368 // client, but has not yet been queued or canceled. The buffer is
369 // considered 'owned' by the client, and the server should not use
372 // Note that when in synchronous-mode (mSynchronousMode == true),
373 // the buffer that's currently attached to the texture may be
374 // dequeued by the client. That means that the current buffer can
375 // be in either the DEQUEUED or QUEUED state. In asynchronous mode,
376 // however, the current buffer is always in the QUEUED state.
377 // aka "owned by producer, ready to be queued"
380 // QUEUED indicates that the buffer has been queued by the client,
381 // and has not since been made available for the client to dequeue.
382 // Attaching the buffer to the texture does NOT transition the
383 // buffer away from the QUEUED state. However, in Synchronous mode
384 // the current buffer may be dequeued by the client under some
385 // circumstances. See the note about the current buffer in the
386 // documentation for DEQUEUED.
387 // aka "owned by BufferQueue, ready to be acquired"
390 // aka "owned by consumer, ready to be released"
394 // mBufferState is the current state of this buffer slot.
395 BufferState mBufferState;
397 // mRequestBufferCalled is used for validating that the client did
398 // call requestBuffer() when told to do so. Technically this is not
399 // needed but useful for debugging and catching client bugs.
400 bool mRequestBufferCalled;
402 // mCrop is the current crop rectangle for this buffer slot.
405 // mTransform is the current transform flags for this buffer slot.
406 // (example: NATIVE_WINDOW_TRANSFORM_ROT_90)
409 // mScalingMode is the current scaling mode for this buffer slot.
410 // (example: NATIVE_WINDOW_SCALING_MODE_FREEZE)
411 uint32_t mScalingMode;
413 // mTimestamp is the current timestamp for this buffer slot. This gets
414 // to set by queueBuffer each time this slot is queued.
417 // mFrameNumber is the number of the queued frame for this slot.
418 uint64_t mFrameNumber;
420 // mEglFence is the EGL sync object that must signal before the buffer
421 // associated with this buffer slot may be dequeued. It is initialized
422 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based
423 // on a compile-time option) set to a new sync object in updateTexImage.
424 EGLSyncKHR mEglFence;
426 // mFence is a fence which will signal when work initiated by the
427 // previous owner of the buffer is finished. When the buffer is FREE,
428 // the fence indicates when the consumer has finished reading
429 // from the buffer, or when the producer has finished writing if it
430 // called cancelBuffer after queueing some writes. When the buffer is
431 // QUEUED, it indicates when the producer has finished filling the
432 // buffer. When the buffer is DEQUEUED or ACQUIRED, the fence has been
433 // passed to the consumer or producer along with ownership of the
434 // buffer, and mFence is empty.
437 // Indicates whether this buffer has been seen by a consumer yet
440 // Indicates whether this buffer needs to be cleaned up by consumer
441 bool mNeedsCleanupOnRelease;
444 // mSlots is the array of buffer slots that must be mirrored on the client
445 // side. This allows buffer ownership to be transferred between the client
446 // and server without sending a GraphicBuffer over binder. The entire array
447 // is initialized to NULL at construction time, and buffers are allocated
448 // for a slot when requestBuffer is called with that slot's index.
449 BufferSlot mSlots[NUM_BUFFER_SLOTS];
451 // mDefaultWidth holds the default width of allocated buffers. It is used
452 // in requestBuffers() if a width and height of zero is specified.
453 uint32_t mDefaultWidth;
455 // mDefaultHeight holds the default height of allocated buffers. It is used
456 // in requestBuffers() if a width and height of zero is specified.
457 uint32_t mDefaultHeight;
459 // mMaxAcquiredBufferCount is the number of buffers that the consumer may
460 // acquire at one time. It defaults to 1 and can be changed by the
461 // consumer via the setMaxAcquiredBufferCount method, but this may only be
462 // done when no producer is connected to the BufferQueue.
464 // This value is used to derive the value returned for the
465 // MIN_UNDEQUEUED_BUFFERS query by the producer.
466 int mMaxAcquiredBufferCount;
468 // mDefaultMaxBufferCount is the default limit on the number of buffers
469 // that will be allocated at one time. This default limit is set by the
470 // consumer. The limit (as opposed to the default limit) may be
471 // overridden by the producer.
472 int mDefaultMaxBufferCount;
474 // mOverrideMaxBufferCount is the limit on the number of buffers that will
475 // be allocated at one time. This value is set by the image producer by
476 // calling setBufferCount. The default is zero, which means the producer
477 // doesn't care about the number of buffers in the pool. In that case
478 // mDefaultMaxBufferCount is used as the limit.
479 int mOverrideMaxBufferCount;
481 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to
482 // allocate new GraphicBuffer objects.
483 sp<IGraphicBufferAlloc> mGraphicBufferAlloc;
485 // mConsumerListener is used to notify the connected consumer of
486 // asynchronous events that it may wish to react to. It is initially set
487 // to NULL and is written by consumerConnect and consumerDisconnect.
488 sp<ConsumerListener> mConsumerListener;
490 // mSynchronousMode whether we're in synchronous mode or not
491 bool mSynchronousMode;
493 // mAllowSynchronousMode whether we allow synchronous mode or not
494 const bool mAllowSynchronousMode;
496 // mConnectedApi indicates the API that is currently connected to this
497 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated
498 // by the connect and disconnect methods.
501 // mDequeueCondition condition used for dequeueBuffer in synchronous mode
502 mutable Condition mDequeueCondition;
504 // mQueue is a FIFO of queued buffers used in synchronous mode
505 typedef Vector<int> Fifo;
508 // mAbandoned indicates that the BufferQueue will no longer be used to
509 // consume images buffers pushed to it using the IGraphicBufferProducer interface.
510 // It is initialized to false, and set to true in the abandon method. A
511 // BufferQueue that has been abandoned will return the NO_INIT error from
512 // all IGraphicBufferProducer methods capable of returning an error.
515 // mName is a string used to identify the BufferQueue in log messages.
516 // It is set by the setName method.
517 String8 mConsumerName;
519 // mMutex is the mutex used to prevent concurrent access to the member
520 // variables of BufferQueue objects. It must be locked whenever the
521 // member variables are accessed.
522 mutable Mutex mMutex;
524 // mFrameCounter is the free running counter, incremented for every buffer queued
525 // with the surface Texture.
526 uint64_t mFrameCounter;
528 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset
529 // by changing the buffer count.
530 bool mBufferHasBeenQueued;
532 // mDefaultBufferFormat can be set so it will override
533 // the buffer format when it isn't specified in dequeueBuffer
534 uint32_t mDefaultBufferFormat;
536 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers
537 uint32_t mConsumerUsageBits;
539 // mTransformHint is used to optimize for screen rotations
540 uint32_t mTransformHint;
543 // ----------------------------------------------------------------------------
544 }; // namespace android
546 #endif // ANDROID_GUI_BUFFERQUEUE_H