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 <optional>
21 #include <string>
22 
23 #include <compositionengine/DisplaySurface.h>
24 #include <compositionengine/impl/HwcBufferCache.h>
25 #include <gui/ConsumerBase.h>
26 #include <gui/IGraphicBufferProducer.h>
27 
28 #include "DisplayIdentification.h"
29 
30 // ---------------------------------------------------------------------------
31 namespace android {
32 // ---------------------------------------------------------------------------
33 
34 class HWComposer;
35 class IProducerListener;
36 
37 /* This DisplaySurface implementation supports virtual displays, where GLES
38  * and/or HWC compose into a buffer that is then passed to an arbitrary
39  * consumer (the sink) running in another process.
40  *
41  * The simplest case is when the virtual display will never use the h/w
42  * composer -- either the h/w composer doesn't support writing to buffers, or
43  * there are more virtual displays than it supports simultaneously. In this
44  * case, the GLES driver works directly with the output buffer queue, and
45  * calls to the VirtualDisplay from SurfaceFlinger and DisplayHardware do
46  * nothing.
47  *
48  * If h/w composer might be used, then each frame will fall into one of three
49  * configurations: GLES-only, HWC-only, and MIXED composition. In all of these,
50  * we must provide a FB target buffer and output buffer for the HWC set() call.
51  *
52  * In GLES-only composition, the GLES driver is given a buffer from the sink to
53  * render into. When the GLES driver queues the buffer to the
54  * VirtualDisplaySurface, the VirtualDisplaySurface holds onto it instead of
55  * immediately queueing it to the sink. The buffer is used as both the FB
56  * target and output buffer for HWC, though on these frames the HWC doesn't
57  * do any work for this display and doesn't write to the output buffer. After
58  * composition is complete, the buffer is queued to the sink.
59  *
60  * In HWC-only composition, the VirtualDisplaySurface dequeues a buffer from
61  * the sink and passes it to HWC as both the FB target buffer and output
62  * buffer. The HWC doesn't need to read from the FB target buffer, but does
63  * write to the output buffer. After composition is complete, the buffer is
64  * queued to the sink.
65  *
66  * On MIXED frames, things become more complicated, since some h/w composer
67  * implementations can't read from and write to the same buffer. This class has
68  * an internal BufferQueue that it uses as a scratch buffer pool. The GLES
69  * driver is given a scratch buffer to render into. When it finishes rendering,
70  * the buffer is queued and then immediately acquired by the
71  * VirtualDisplaySurface. The scratch buffer is then used as the FB target
72  * buffer for HWC, and a separate buffer is dequeued from the sink and used as
73  * the HWC output buffer. When HWC composition is complete, the scratch buffer
74  * is released and the output buffer is queued to the sink.
75  */
76 class VirtualDisplaySurface : public compositionengine::DisplaySurface,
77                               public BnGraphicBufferProducer,
78                               private ConsumerBase {
79 public:
80     VirtualDisplaySurface(HWComposer& hwc, const std::optional<DisplayId>& displayId,
81                           const sp<IGraphicBufferProducer>& sink,
82                           const sp<IGraphicBufferProducer>& bqProducer,
83                           const sp<IGraphicBufferConsumer>& bqConsumer, const std::string& name);
84 
85     //
86     // DisplaySurface interface
87     //
88     virtual status_t beginFrame(bool mustRecompose);
89     virtual status_t prepareFrame(CompositionType compositionType);
90     virtual status_t advanceFrame();
91     virtual void onFrameCommitted();
92     virtual void dumpAsString(String8& result) const;
93     virtual void resizeBuffers(const uint32_t w, const uint32_t h);
94     virtual const sp<Fence>& getClientTargetAcquireFence() const override;
95 
96 private:
97     enum Source {SOURCE_SINK = 0, SOURCE_SCRATCH = 1};
98 
99     virtual ~VirtualDisplaySurface();
100 
101     //
102     // IGraphicBufferProducer interface, used by the GLES driver.
103     //
104     virtual status_t requestBuffer(int pslot, sp<GraphicBuffer>* outBuf);
105     virtual status_t setMaxDequeuedBufferCount(int maxDequeuedBuffers);
106     virtual status_t setAsyncMode(bool async);
107     virtual status_t dequeueBuffer(int* pslot, sp<Fence>* fence, uint32_t w, uint32_t h,
108                                    PixelFormat format, uint64_t usage, uint64_t* outBufferAge,
109                                    FrameEventHistoryDelta* outTimestamps);
110     virtual status_t detachBuffer(int slot);
111     virtual status_t detachNextBuffer(sp<GraphicBuffer>* outBuffer,
112             sp<Fence>* outFence);
113     virtual status_t attachBuffer(int* slot, const sp<GraphicBuffer>& buffer);
114     virtual status_t queueBuffer(int pslot,
115             const QueueBufferInput& input, QueueBufferOutput* output);
116     virtual status_t cancelBuffer(int pslot, const sp<Fence>& fence);
117     virtual int query(int what, int* value);
118     virtual status_t connect(const sp<IProducerListener>& listener,
119             int api, bool producerControlledByApp, QueueBufferOutput* output);
120     virtual status_t disconnect(int api, DisconnectMode mode);
121     virtual status_t setSidebandStream(const sp<NativeHandle>& stream);
122     virtual void allocateBuffers(uint32_t width, uint32_t height,
123             PixelFormat format, uint64_t usage);
124     virtual status_t allowAllocation(bool allow);
125     virtual status_t setGenerationNumber(uint32_t generationNumber);
126     virtual String8 getConsumerName() const override;
127     virtual status_t setSharedBufferMode(bool sharedBufferMode) override;
128     virtual status_t setAutoRefresh(bool autoRefresh) override;
129     virtual status_t setDequeueTimeout(nsecs_t timeout) override;
130     virtual status_t getLastQueuedBuffer(sp<GraphicBuffer>* outBuffer,
131             sp<Fence>* outFence, float outTransformMatrix[16]) override;
132     virtual status_t getUniqueId(uint64_t* outId) const override;
133     virtual status_t getConsumerUsage(uint64_t* outUsage) const override;
134 
135     //
136     // Utility methods
137     //
138     static Source fbSourceForCompositionType(CompositionType type);
139     status_t dequeueBuffer(Source source, PixelFormat format, uint64_t usage,
140             int* sslot, sp<Fence>* fence);
141     void updateQueueBufferOutput(QueueBufferOutput&& qbo);
142     void resetPerFrameState();
143     status_t refreshOutputBuffer();
144 
145     // Both the sink and scratch buffer pools have their own set of slots
146     // ("source slots", or "sslot"). We have to merge these into the single
147     // set of slots used by the GLES producer ("producer slots" or "pslot") and
148     // internally in the VirtualDisplaySurface. To minimize the number of times
149     // a producer slot switches which source it comes from, we map source slot
150     // numbers to producer slot numbers differently for each source.
151     static int mapSource2ProducerSlot(Source source, int sslot);
152     static int mapProducer2SourceSlot(Source source, int pslot);
153 
154     //
155     // Immutable after construction
156     //
157     HWComposer& mHwc;
158     const std::optional<DisplayId> mDisplayId;
159     const std::string mDisplayName;
160     sp<IGraphicBufferProducer> mSource[2]; // indexed by SOURCE_*
161     uint32_t mDefaultOutputFormat;
162 
163     //
164     // Inter-frame state
165     //
166 
167     // To avoid buffer reallocations, we track the buffer usage and format
168     // we used on the previous frame and use it again on the new frame. If
169     // the composition type changes or the GLES driver starts requesting
170     // different usage/format, we'll get a new buffer.
171     uint32_t mOutputFormat;
172     uint64_t mOutputUsage;
173 
174     // Since we present a single producer interface to the GLES driver, but
175     // are internally muxing between the sink and scratch producers, we have
176     // to keep track of which source last returned each producer slot from
177     // dequeueBuffer. Each bit in mProducerSlotSource corresponds to a producer
178     // slot. Both mProducerSlotSource and mProducerBuffers are indexed by a
179     // "producer slot"; see the mapSlot*() functions.
180     uint64_t mProducerSlotSource;
181     sp<GraphicBuffer> mProducerBuffers[BufferQueueDefs::NUM_BUFFER_SLOTS];
182 
183     // The QueueBufferOutput with the latest info from the sink, and with the
184     // transform hint cleared. Since we defer queueBuffer from the GLES driver
185     // to the sink, we have to return the previous version.
186     // Moves instead of copies are performed to avoid duplicate
187     // FrameEventHistoryDeltas.
188     QueueBufferOutput mQueueBufferOutput;
189 
190     // Details of the current sink buffer. These become valid when a buffer is
191     // dequeued from the sink, and are used when queueing the buffer.
192     uint32_t mSinkBufferWidth, mSinkBufferHeight;
193 
194     //
195     // Intra-frame state
196     //
197 
198     // Composition type and GLES buffer source for the current frame.
199     // Valid after prepareFrame(), cleared in onFrameCommitted.
200     CompositionType mCompositionType;
201 
202     // mFbFence is the fence HWC should wait for before reading the framebuffer
203     // target buffer.
204     sp<Fence> mFbFence;
205 
206     // mOutputFence is the fence HWC should wait for before writing to the
207     // output buffer.
208     sp<Fence> mOutputFence;
209 
210     // Producer slot numbers for the buffers to use for HWC framebuffer target
211     // and output.
212     int mFbProducerSlot;
213     int mOutputProducerSlot;
214 
215     // Debug only -- track the sequence of events in each frame so we can make
216     // sure they happen in the order we expect. This class implicitly models
217     // a state machine; this enum/variable makes it explicit.
218     //
219     // +-----------+-------------------+-------------+
220     // | State     | Event             || Next State |
221     // +-----------+-------------------+-------------+
222     // | IDLE      | beginFrame        || BEGUN      |
223     // | BEGUN     | prepareFrame      || PREPARED   |
224     // | PREPARED  | dequeueBuffer [1] || GLES       |
225     // | PREPARED  | advanceFrame [2]  || HWC        |
226     // | GLES      | queueBuffer       || GLES_DONE  |
227     // | GLES_DONE | advanceFrame      || HWC        |
228     // | HWC       | onFrameCommitted  || IDLE       |
229     // +-----------+-------------------++------------+
230     // [1] COMPOSITION_GLES and COMPOSITION_MIXED frames.
231     // [2] COMPOSITION_HWC frames.
232     //
233     enum DbgState {
234         // no buffer dequeued, don't know anything about the next frame
235         DBG_STATE_IDLE,
236         // output buffer dequeued, framebuffer source not yet known
237         DBG_STATE_BEGUN,
238         // output buffer dequeued, framebuffer source known but not provided
239         // to GLES yet.
240         DBG_STATE_PREPARED,
241         // GLES driver has a buffer dequeued
242         DBG_STATE_GLES,
243         // GLES driver has queued the buffer, we haven't sent it to HWC yet
244         DBG_STATE_GLES_DONE,
245         // HWC has the buffer for this frame
246         DBG_STATE_HWC,
247     };
248     DbgState mDbgState;
249     CompositionType mDbgLastCompositionType;
250 
251     const char* dbgStateStr() const;
252     static const char* dbgSourceStr(Source s);
253 
254     bool mMustRecompose;
255 
256     compositionengine::impl::HwcBufferCache mHwcBufferCache;
257 
258     bool mForceHwcCopy;
259 };
260 
261 // ---------------------------------------------------------------------------
262 } // namespace android
263 // ---------------------------------------------------------------------------
264 
265 #endif // ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
266