1 /*
2  * Copyright 2013 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
18 #define ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
19 
20 #include "DisplaySurface.h"
21 #include "HWComposerBufferCache.h"
22 
23 #include <gui/ConsumerBase.h>
24 #include <gui/IGraphicBufferProducer.h>
25 
26 // ---------------------------------------------------------------------------
27 namespace android {
28 // ---------------------------------------------------------------------------
29 
30 class HWComposer;
31 class IProducerListener;
32 
33 /* This DisplaySurface implementation supports virtual displays, where GLES
34  * and/or HWC compose into a buffer that is then passed to an arbitrary
35  * consumer (the sink) running in another process.
36  *
37  * The simplest case is when the virtual display will never use the h/w
38  * composer -- either the h/w composer doesn't support writing to buffers, or
39  * there are more virtual displays than it supports simultaneously. In this
40  * case, the GLES driver works directly with the output buffer queue, and
41  * calls to the VirtualDisplay from SurfaceFlinger and DisplayHardware do
42  * nothing.
43  *
44  * If h/w composer might be used, then each frame will fall into one of three
45  * configurations: GLES-only, HWC-only, and MIXED composition. In all of these,
46  * we must provide a FB target buffer and output buffer for the HWC set() call.
47  *
48  * In GLES-only composition, the GLES driver is given a buffer from the sink to
49  * render into. When the GLES driver queues the buffer to the
50  * VirtualDisplaySurface, the VirtualDisplaySurface holds onto it instead of
51  * immediately queueing it to the sink. The buffer is used as both the FB
52  * target and output buffer for HWC, though on these frames the HWC doesn't
53  * do any work for this display and doesn't write to the output buffer. After
54  * composition is complete, the buffer is queued to the sink.
55  *
56  * In HWC-only composition, the VirtualDisplaySurface dequeues a buffer from
57  * the sink and passes it to HWC as both the FB target buffer and output
58  * buffer. The HWC doesn't need to read from the FB target buffer, but does
59  * write to the output buffer. After composition is complete, the buffer is
60  * queued to the sink.
61  *
62  * On MIXED frames, things become more complicated, since some h/w composer
63  * implementations can't read from and write to the same buffer. This class has
64  * an internal BufferQueue that it uses as a scratch buffer pool. The GLES
65  * driver is given a scratch buffer to render into. When it finishes rendering,
66  * the buffer is queued and then immediately acquired by the
67  * VirtualDisplaySurface. The scratch buffer is then used as the FB target
68  * buffer for HWC, and a separate buffer is dequeued from the sink and used as
69  * the HWC output buffer. When HWC composition is complete, the scratch buffer
70  * is released and the output buffer is queued to the sink.
71  */
72 class VirtualDisplaySurface : public DisplaySurface,
73                               public BnGraphicBufferProducer,
74                               private ConsumerBase {
75 public:
76     VirtualDisplaySurface(HWComposer& hwc, int32_t dispId,
77             const sp<IGraphicBufferProducer>& sink,
78             const sp<IGraphicBufferProducer>& bqProducer,
79             const sp<IGraphicBufferConsumer>& bqConsumer,
80             const String8& name);
81 
82     //
83     // DisplaySurface interface
84     //
85     virtual status_t beginFrame(bool mustRecompose);
86     virtual status_t prepareFrame(CompositionType compositionType);
87     virtual status_t advanceFrame();
88     virtual void onFrameCommitted();
89     virtual void dumpAsString(String8& result) const;
90     virtual void resizeBuffers(const uint32_t w, const uint32_t h);
91     virtual const sp<Fence>& getClientTargetAcquireFence() const override;
92 
93 private:
94     enum Source {SOURCE_SINK = 0, SOURCE_SCRATCH = 1};
95 
96     virtual ~VirtualDisplaySurface();
97 
98     //
99     // IGraphicBufferProducer interface, used by the GLES driver.
100     //
101     virtual status_t requestBuffer(int pslot, sp<GraphicBuffer>* outBuf);
102     virtual status_t setMaxDequeuedBufferCount(int maxDequeuedBuffers);
103     virtual status_t setAsyncMode(bool async);
104     virtual status_t dequeueBuffer(int* pslot, sp<Fence>* fence, uint32_t w, uint32_t h,
105                                    PixelFormat format, uint64_t usage, uint64_t* outBufferAge,
106                                    FrameEventHistoryDelta* outTimestamps);
107     virtual status_t detachBuffer(int slot);
108     virtual status_t detachNextBuffer(sp<GraphicBuffer>* outBuffer,
109             sp<Fence>* outFence);
110     virtual status_t attachBuffer(int* slot, const sp<GraphicBuffer>& buffer);
111     virtual status_t queueBuffer(int pslot,
112             const QueueBufferInput& input, QueueBufferOutput* output);
113     virtual status_t cancelBuffer(int pslot, const sp<Fence>& fence);
114     virtual int query(int what, int* value);
115     virtual status_t connect(const sp<IProducerListener>& listener,
116             int api, bool producerControlledByApp, QueueBufferOutput* output);
117     virtual status_t disconnect(int api, DisconnectMode mode);
118     virtual status_t setSidebandStream(const sp<NativeHandle>& stream);
119     virtual void allocateBuffers(uint32_t width, uint32_t height,
120             PixelFormat format, uint64_t usage);
121     virtual status_t allowAllocation(bool allow);
122     virtual status_t setGenerationNumber(uint32_t generationNumber);
123     virtual String8 getConsumerName() const override;
124     virtual status_t setSharedBufferMode(bool sharedBufferMode) override;
125     virtual status_t setAutoRefresh(bool autoRefresh) override;
126     virtual status_t setDequeueTimeout(nsecs_t timeout) override;
127     virtual status_t getLastQueuedBuffer(sp<GraphicBuffer>* outBuffer,
128             sp<Fence>* outFence, float outTransformMatrix[16]) override;
129     virtual status_t getUniqueId(uint64_t* outId) const override;
130     virtual status_t getConsumerUsage(uint64_t* outUsage) const override;
131 
132     //
133     // Utility methods
134     //
135     static Source fbSourceForCompositionType(CompositionType type);
136     status_t dequeueBuffer(Source source, PixelFormat format, uint64_t usage,
137             int* sslot, sp<Fence>* fence);
138     void updateQueueBufferOutput(QueueBufferOutput&& qbo);
139     void resetPerFrameState();
140     status_t refreshOutputBuffer();
141 
142     // Both the sink and scratch buffer pools have their own set of slots
143     // ("source slots", or "sslot"). We have to merge these into the single
144     // set of slots used by the GLES producer ("producer slots" or "pslot") and
145     // internally in the VirtualDisplaySurface. To minimize the number of times
146     // a producer slot switches which source it comes from, we map source slot
147     // numbers to producer slot numbers differently for each source.
148     static int mapSource2ProducerSlot(Source source, int sslot);
149     static int mapProducer2SourceSlot(Source source, int pslot);
150 
151     //
152     // Immutable after construction
153     //
154     HWComposer& mHwc;
155     const int32_t mDisplayId;
156     const String8 mDisplayName;
157     sp<IGraphicBufferProducer> mSource[2]; // indexed by SOURCE_*
158     uint32_t mDefaultOutputFormat;
159 
160     //
161     // Inter-frame state
162     //
163 
164     // To avoid buffer reallocations, we track the buffer usage and format
165     // we used on the previous frame and use it again on the new frame. If
166     // the composition type changes or the GLES driver starts requesting
167     // different usage/format, we'll get a new buffer.
168     uint32_t mOutputFormat;
169     uint64_t mOutputUsage;
170 
171     // Since we present a single producer interface to the GLES driver, but
172     // are internally muxing between the sink and scratch producers, we have
173     // to keep track of which source last returned each producer slot from
174     // dequeueBuffer. Each bit in mProducerSlotSource corresponds to a producer
175     // slot. Both mProducerSlotSource and mProducerBuffers are indexed by a
176     // "producer slot"; see the mapSlot*() functions.
177     uint64_t mProducerSlotSource;
178     sp<GraphicBuffer> mProducerBuffers[BufferQueueDefs::NUM_BUFFER_SLOTS];
179 
180     // The QueueBufferOutput with the latest info from the sink, and with the
181     // transform hint cleared. Since we defer queueBuffer from the GLES driver
182     // to the sink, we have to return the previous version.
183     // Moves instead of copies are performed to avoid duplicate
184     // FrameEventHistoryDeltas.
185     QueueBufferOutput mQueueBufferOutput;
186 
187     // Details of the current sink buffer. These become valid when a buffer is
188     // dequeued from the sink, and are used when queueing the buffer.
189     uint32_t mSinkBufferWidth, mSinkBufferHeight;
190 
191     //
192     // Intra-frame state
193     //
194 
195     // Composition type and GLES buffer source for the current frame.
196     // Valid after prepareFrame(), cleared in onFrameCommitted.
197     CompositionType mCompositionType;
198 
199     // mFbFence is the fence HWC should wait for before reading the framebuffer
200     // target buffer.
201     sp<Fence> mFbFence;
202 
203     // mOutputFence is the fence HWC should wait for before writing to the
204     // output buffer.
205     sp<Fence> mOutputFence;
206 
207     // Producer slot numbers for the buffers to use for HWC framebuffer target
208     // and output.
209     int mFbProducerSlot;
210     int mOutputProducerSlot;
211 
212     // Debug only -- track the sequence of events in each frame so we can make
213     // sure they happen in the order we expect. This class implicitly models
214     // a state machine; this enum/variable makes it explicit.
215     //
216     // +-----------+-------------------+-------------+
217     // | State     | Event             || Next State |
218     // +-----------+-------------------+-------------+
219     // | IDLE      | beginFrame        || BEGUN      |
220     // | BEGUN     | prepareFrame      || PREPARED   |
221     // | PREPARED  | dequeueBuffer [1] || GLES       |
222     // | PREPARED  | advanceFrame [2]  || HWC        |
223     // | GLES      | queueBuffer       || GLES_DONE  |
224     // | GLES_DONE | advanceFrame      || HWC        |
225     // | HWC       | onFrameCommitted  || IDLE       |
226     // +-----------+-------------------++------------+
227     // [1] COMPOSITION_GLES and COMPOSITION_MIXED frames.
228     // [2] COMPOSITION_HWC frames.
229     //
230     enum DbgState {
231         // no buffer dequeued, don't know anything about the next frame
232         DBG_STATE_IDLE,
233         // output buffer dequeued, framebuffer source not yet known
234         DBG_STATE_BEGUN,
235         // output buffer dequeued, framebuffer source known but not provided
236         // to GLES yet.
237         DBG_STATE_PREPARED,
238         // GLES driver has a buffer dequeued
239         DBG_STATE_GLES,
240         // GLES driver has queued the buffer, we haven't sent it to HWC yet
241         DBG_STATE_GLES_DONE,
242         // HWC has the buffer for this frame
243         DBG_STATE_HWC,
244     };
245     DbgState mDbgState;
246     CompositionType mDbgLastCompositionType;
247 
248     const char* dbgStateStr() const;
249     static const char* dbgSourceStr(Source s);
250 
251     bool mMustRecompose;
252 
253     HWComposerBufferCache mHwcBufferCache;
254 
255     bool mForceHwcCopy;
256 };
257 
258 // ---------------------------------------------------------------------------
259 } // namespace android
260 // ---------------------------------------------------------------------------
261 
262 #endif // ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
263