BufferQueue.h revision 4c00cc11141da7d159eb2323b186ed344115c0f1
1/* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#ifndef ANDROID_GUI_BUFFERQUEUE_H 18#define ANDROID_GUI_BUFFERQUEUE_H 19 20#include <EGL/egl.h> 21#include <EGL/eglext.h> 22 23#include <gui/IGraphicBufferAlloc.h> 24#include <gui/IGraphicBufferProducer.h> 25 26#include <ui/Fence.h> 27#include <ui/GraphicBuffer.h> 28 29#include <utils/String8.h> 30#include <utils/Vector.h> 31#include <utils/threads.h> 32 33namespace android { 34// ---------------------------------------------------------------------------- 35 36class BufferQueue : public BnGraphicBufferProducer { 37public: 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 }; 43 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 }; 47 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. 59 // 60 // This is called without any lock held and can be called concurrently 61 // by multiple threads. 62 virtual void onFrameAvailable() = 0; 63 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 68 // 69 // This is called without any lock held and can be called concurrently 70 // by multiple threads. 71 virtual void onBuffersReleased() = 0; 72 }; 73 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. 77 // 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 82 // weak references. 83 class ProxyConsumerListener : public BufferQueue::ConsumerListener { 84 public: 85 86 ProxyConsumerListener(const wp<BufferQueue::ConsumerListener>& consumerListener); 87 virtual ~ProxyConsumerListener(); 88 virtual void onFrameAvailable(); 89 virtual void onBuffersReleased(); 90 91 private: 92 93 // mConsumerListener is a weak reference to the ConsumerListener. This is 94 // the raison d'etre of ProxyConsumerListener. 95 wp<BufferQueue::ConsumerListener> mConsumerListener; 96 }; 97 98 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(); 106 107 virtual int query(int what, int* value); 108 109 // 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); 113 114 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 115 116 // 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 120 // unmodified. 121 // 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 125 // immediately. 126 // 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); 133 134 // 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 138 // client. 139 virtual status_t queueBuffer(int buf, 140 const QueueBufferInput& input, QueueBufferOutput* output); 141 142 virtual void cancelBuffer(int buf, const sp<Fence>& fence); 143 144 // 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); 150 151 // 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. 154 // 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); 158 159 // 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 163 // succeed again. 164 // 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); 168 169 // 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; 172 173 // public facing structure for BufferSlot 174 struct BufferItem { 175 176 BufferItem() 177 : 178 mTransform(0), 179 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 180 mTimestamp(0), 181 mFrameNumber(0), 182 mBuf(INVALID_BUFFER_SLOT) { 183 mCrop.makeInvalid(); 184 } 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; 189 190 // mCrop is the current crop rectangle for this buffer slot. 191 Rect mCrop; 192 193 // mTransform is the current transform flags for this buffer slot. 194 uint32_t mTransform; 195 196 // mScalingMode is the current scaling mode for this buffer slot. 197 uint32_t mScalingMode; 198 199 // mTimestamp is the current timestamp for this buffer slot. This gets 200 // to set by queueBuffer each time this slot is queued. 201 int64_t mTimestamp; 202 203 // mFrameNumber is the number of the queued frame for this slot. 204 uint64_t mFrameNumber; 205 206 // mBuf is the slot index of this buffer 207 int mBuf; 208 209 // mFence is a fence that will signal when the buffer is idle. 210 sp<Fence> mFence; 211 }; 212 213 // The following public functions is the consumer facing interface 214 215 // 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 221 // buffer. 222 status_t acquireBuffer(BufferItem *buffer); 223 224 // releaseBuffer releases a buffer slot from the consumer back to the 225 // BufferQueue pending a fence sync. 226 // 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 230 // buffer. 231 // 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); 236 237 // 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); 242 243 // 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 246 // fail. 247 status_t consumerDisconnect(); 248 249 // 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); 253 254 // 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); 257 258 // 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); 262 263 // 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); 267 268 // isSynchronousMode returns whether the BufferQueue is currently in 269 // synchronous mode. 270 bool isSynchronousMode() const; 271 272 // setConsumerName sets the name used in logging 273 void setConsumerName(const String8& name); 274 275 // setDefaultBufferFormat allows the BufferQueue to create 276 // GraphicBuffers of a defaultFormat if no format is specified 277 // in dequeueBuffer 278 status_t setDefaultBufferFormat(uint32_t defaultFormat); 279 280 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer 281 status_t setConsumerUsageBits(uint32_t usage); 282 283 // setTransformHint bakes in rotation to buffers so overlays can be used 284 status_t setTransformHint(uint32_t hint); 285 286private: 287 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 288 // for the given slot. 289 void freeBufferLocked(int index); 290 291 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 292 // EGLImage) for all slots. 293 void freeAllBuffersLocked(); 294 295 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 296 // and EGLImage) for all slots except the head of mQueue 297 void freeAllBuffersExceptHeadLocked(); 298 299 // 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(); 303 304 // 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(); 308 309 // setDefaultMaxBufferCountLocked sets the maximum number of buffer slots 310 // that will be used if the producer does not override the buffer slot 311 // count. 312 status_t setDefaultMaxBufferCountLocked(int count); 313 314 // getMinBufferCountLocked returns the minimum number of buffers allowed 315 // given the current BufferQueue state. 316 int getMinMaxBufferCountLocked() const; 317 318 // getMinUndequeuedBufferCountLocked returns the minimum number of buffers 319 // that must remain in a state other than DEQUEUED. 320 int getMinUndequeuedBufferCountLocked() const; 321 322 // getMaxBufferCountLocked returns the maximum number of buffers that can 323 // be allocated at once. This value depends upon the following member 324 // variables: 325 // 326 // mSynchronousMode 327 // mMaxAcquiredBufferCount 328 // mDefaultMaxBufferCount 329 // mOverrideMaxBufferCount 330 // 331 // Any time one of these member variables is changed while a producer is 332 // connected, mDequeueCondition must be broadcast. 333 int getMaxBufferCountLocked() const; 334 335 struct BufferSlot { 336 337 BufferSlot() 338 : mEglDisplay(EGL_NO_DISPLAY), 339 mBufferState(BufferSlot::FREE), 340 mRequestBufferCalled(false), 341 mTransform(0), 342 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 343 mTimestamp(0), 344 mFrameNumber(0), 345 mEglFence(EGL_NO_SYNC_KHR), 346 mAcquireCalled(false), 347 mNeedsCleanupOnRelease(false) { 348 mCrop.makeInvalid(); 349 } 350 351 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 352 // if no buffer has been allocated. 353 sp<GraphicBuffer> mGraphicBuffer; 354 355 // mEglDisplay is the EGLDisplay used to create mEglImage. 356 EGLDisplay mEglDisplay; 357 358 // BufferState represents the different states in which a buffer slot 359 // can be. 360 enum BufferState { 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" 365 FREE = 0, 366 367 // 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 370 // it for anything. 371 // 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" 378 DEQUEUED = 1, 379 380 // 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" 388 QUEUED = 2, 389 390 // aka "owned by consumer, ready to be released" 391 ACQUIRED = 3 392 }; 393 394 // mBufferState is the current state of this buffer slot. 395 BufferState mBufferState; 396 397 // 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; 401 402 // mCrop is the current crop rectangle for this buffer slot. 403 Rect mCrop; 404 405 // mTransform is the current transform flags for this buffer slot. 406 // (example: NATIVE_WINDOW_TRANSFORM_ROT_90) 407 uint32_t mTransform; 408 409 // mScalingMode is the current scaling mode for this buffer slot. 410 // (example: NATIVE_WINDOW_SCALING_MODE_FREEZE) 411 uint32_t mScalingMode; 412 413 // mTimestamp is the current timestamp for this buffer slot. This gets 414 // to set by queueBuffer each time this slot is queued. 415 int64_t mTimestamp; 416 417 // mFrameNumber is the number of the queued frame for this slot. 418 uint64_t mFrameNumber; 419 420 // 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; 425 426 // 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. 435 sp<Fence> mFence; 436 437 // Indicates whether this buffer has been seen by a consumer yet 438 bool mAcquireCalled; 439 440 // Indicates whether this buffer needs to be cleaned up by consumer 441 bool mNeedsCleanupOnRelease; 442 }; 443 444 // 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]; 450 451 // 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; 454 455 // 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; 458 459 // 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. 463 // 464 // This value is used to derive the value returned for the 465 // MIN_UNDEQUEUED_BUFFERS query by the producer. 466 int mMaxAcquiredBufferCount; 467 468 // 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; 473 474 // 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; 480 481 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 482 // allocate new GraphicBuffer objects. 483 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 484 485 // 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; 489 490 // mSynchronousMode whether we're in synchronous mode or not 491 bool mSynchronousMode; 492 493 // mAllowSynchronousMode whether we allow synchronous mode or not 494 const bool mAllowSynchronousMode; 495 496 // 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. 499 int mConnectedApi; 500 501 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 502 mutable Condition mDequeueCondition; 503 504 // mQueue is a FIFO of queued buffers used in synchronous mode 505 typedef Vector<int> Fifo; 506 Fifo mQueue; 507 508 // 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. 513 bool mAbandoned; 514 515 // mName is a string used to identify the BufferQueue in log messages. 516 // It is set by the setName method. 517 String8 mConsumerName; 518 519 // 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; 523 524 // mFrameCounter is the free running counter, incremented for every buffer queued 525 // with the surface Texture. 526 uint64_t mFrameCounter; 527 528 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset 529 // by changing the buffer count. 530 bool mBufferHasBeenQueued; 531 532 // mDefaultBufferFormat can be set so it will override 533 // the buffer format when it isn't specified in dequeueBuffer 534 uint32_t mDefaultBufferFormat; 535 536 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 537 uint32_t mConsumerUsageBits; 538 539 // mTransformHint is used to optimize for screen rotations 540 uint32_t mTransformHint; 541}; 542 543// ---------------------------------------------------------------------------- 544}; // namespace android 545 546#endif // ANDROID_GUI_BUFFERQUEUE_H 547