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+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
+#define ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
+
+#include <gui/IGraphicBufferProducer.h>
+
+#include "DisplaySurface.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class HWComposer;
+class IProducerListener;
+
+/* This DisplaySurface implementation supports virtual displays, where GLES
+ * and/or HWC compose into a buffer that is then passed to an arbitrary
+ * consumer (the sink) running in another process.
+ *
+ * The simplest case is when the virtual display will never use the h/w
+ * composer -- either the h/w composer doesn't support writing to buffers, or
+ * there are more virtual displays than it supports simultaneously. In this
+ * case, the GLES driver works directly with the output buffer queue, and
+ * calls to the VirtualDisplay from SurfaceFlinger and DisplayHardware do
+ * nothing.
+ *
+ * If h/w composer might be used, then each frame will fall into one of three
+ * configurations: GLES-only, HWC-only, and MIXED composition. In all of these,
+ * we must provide a FB target buffer and output buffer for the HWC set() call.
+ *
+ * In GLES-only composition, the GLES driver is given a buffer from the sink to
+ * render into. When the GLES driver queues the buffer to the
+ * VirtualDisplaySurface, the VirtualDisplaySurface holds onto it instead of
+ * immediately queueing it to the sink. The buffer is used as both the FB
+ * target and output buffer for HWC, though on these frames the HWC doesn't
+ * do any work for this display and doesn't write to the output buffer. After
+ * composition is complete, the buffer is queued to the sink.
+ *
+ * In HWC-only composition, the VirtualDisplaySurface dequeues a buffer from
+ * the sink and passes it to HWC as both the FB target buffer and output
+ * buffer. The HWC doesn't need to read from the FB target buffer, but does
+ * write to the output buffer. After composition is complete, the buffer is
+ * queued to the sink.
+ *
+ * On MIXED frames, things become more complicated, since some h/w composer
+ * implementations can't read from and write to the same buffer. This class has
+ * an internal BufferQueue that it uses as a scratch buffer pool. The GLES
+ * driver is given a scratch buffer to render into. When it finishes rendering,
+ * the buffer is queued and then immediately acquired by the
+ * VirtualDisplaySurface. The scratch buffer is then used as the FB target
+ * buffer for HWC, and a separate buffer is dequeued from the sink and used as
+ * the HWC output buffer. When HWC composition is complete, the scratch buffer
+ * is released and the output buffer is queued to the sink.
+ */
+class VirtualDisplaySurface : public DisplaySurface,
+ public BnGraphicBufferProducer {
+public:
+ VirtualDisplaySurface(int32_t dispId,
+ const sp<IGraphicBufferProducer>& sink,
+ const sp<IGraphicBufferProducer>& bqProducer,
+ const sp<StreamConsumer>& bqConsumer,
+ const String8& name);
+
+ //
+ // DisplaySurface interface
+ //
+ virtual status_t beginFrame(bool mustRecompose);
+ virtual status_t prepareFrame(CompositionType compositionType);
+ virtual status_t compositionComplete();
+ virtual status_t advanceFrame();
+ virtual void onFrameCommitted();
+ virtual void resizeBuffers(const uint32_t w, const uint32_t h);
+
+ virtual status_t setReleaseFenceFd(int fenceFd) { return INVALID_OPERATION; }
+ virtual int GetPrevDispAcquireFd() { return -1; };
+
+private:
+ enum Source {SOURCE_SINK = 0, SOURCE_SCRATCH = 1};
+
+ virtual ~VirtualDisplaySurface();
+
+ //
+ // IGraphicBufferProducer interface, used by the GLES driver.
+ //
+ virtual status_t requestBuffer(int pslot, sp<GraphicBuffer>* outBuf);
+ virtual status_t setBufferCount(int bufferCount);
+ virtual status_t dequeueBuffer(int* pslot, sp<Fence>* fence, bool async,
+ uint32_t w, uint32_t h, uint32_t format, uint32_t usage);
+ virtual status_t detachBuffer(int slot);
+ virtual status_t detachNextBuffer(sp<GraphicBuffer>* outBuffer,
+ sp<Fence>* outFence);
+ virtual status_t attachBuffer(int* slot, const sp<GraphicBuffer>& buffer);
+ virtual status_t queueBuffer(int pslot,
+ const QueueBufferInput& input, QueueBufferOutput* output);
+ virtual void cancelBuffer(int pslot, const sp<Fence>& fence);
+ virtual int query(int what, int* value);
+#if ANDROID_VERSION >= 21
+ virtual status_t connect(const sp<IProducerListener>& listener,
+ int api, bool producerControlledByApp, QueueBufferOutput* output);
+#else
+ virtual status_t connect(const sp<IBinder>& token,
+ int api, bool producerControlledByApp, QueueBufferOutput* output);
+#endif
+ virtual status_t disconnect(int api);
+#if ANDROID_VERSION >= 21
+ virtual status_t setSidebandStream(const sp<NativeHandle>& stream);
+#endif
+ virtual void allocateBuffers(bool async, uint32_t width, uint32_t height,
+ uint32_t format, uint32_t usage);
+
+ //
+ // Utility methods
+ //
+ static Source fbSourceForCompositionType(CompositionType type);
+ status_t dequeueBuffer(Source source, uint32_t format, uint32_t usage,
+ int* sslot, sp<Fence>* fence);
+ void updateQueueBufferOutput(const QueueBufferOutput& qbo);
+ void resetPerFrameState();
+ status_t refreshOutputBuffer();
+
+ // Both the sink and scratch buffer pools have their own set of slots
+ // ("source slots", or "sslot"). We have to merge these into the single
+ // set of slots used by the GLES producer ("producer slots" or "pslot") and
+ // internally in the VirtualDisplaySurface. To minimize the number of times
+ // a producer slot switches which source it comes from, we map source slot
+ // numbers to producer slot numbers differently for each source.
+ static int mapSource2ProducerSlot(Source source, int sslot);
+ static int mapProducer2SourceSlot(Source source, int pslot);
+
+ //
+ // Immutable after construction
+ //
+ const int32_t mDisplayId;
+ const String8 mDisplayName;
+ sp<IGraphicBufferProducer> mSource[2]; // indexed by SOURCE_*
+ uint32_t mDefaultOutputFormat;
+
+ //
+ // Inter-frame state
+ //
+
+ // To avoid buffer reallocations, we track the buffer usage and format
+ // we used on the previous frame and use it again on the new frame. If
+ // the composition type changes or the GLES driver starts requesting
+ // different usage/format, we'll get a new buffer.
+ uint32_t mOutputFormat;
+ uint32_t mOutputUsage;
+
+ // Since we present a single producer interface to the GLES driver, but
+ // are internally muxing between the sink and scratch producers, we have
+ // to keep track of which source last returned each producer slot from
+ // dequeueBuffer. Each bit in mProducerSlotSource corresponds to a producer
+ // slot. Both mProducerSlotSource and mProducerBuffers are indexed by a
+ // "producer slot"; see the mapSlot*() functions.
+ uint64_t mProducerSlotSource;
+ sp<GraphicBuffer> mProducerBuffers[BufferQueue::NUM_BUFFER_SLOTS];
+
+ // The QueueBufferOutput with the latest info from the sink, and with the
+ // transform hint cleared. Since we defer queueBuffer from the GLES driver
+ // to the sink, we have to return the previous version.
+ QueueBufferOutput mQueueBufferOutput;
+
+ // Details of the current sink buffer. These become valid when a buffer is
+ // dequeued from the sink, and are used when queueing the buffer.
+ uint32_t mSinkBufferWidth, mSinkBufferHeight;
+
+ //
+ // Intra-frame state
+ //
+
+ // Composition type and GLES buffer source for the current frame.
+ // Valid after prepareFrame(), cleared in onFrameCommitted.
+ CompositionType mCompositionType;
+
+ // mFbFence is the fence HWC should wait for before reading the framebuffer
+ // target buffer.
+ sp<Fence> mFbFence;
+
+ // mOutputFence is the fence HWC should wait for before writing to the
+ // output buffer.
+ sp<Fence> mOutputFence;
+
+ // Producer slot numbers for the buffers to use for HWC framebuffer target
+ // and output.
+ int mFbProducerSlot;
+ int mOutputProducerSlot;
+
+ // Debug only -- track the sequence of events in each frame so we can make
+ // sure they happen in the order we expect. This class implicitly models
+ // a state machine; this enum/variable makes it explicit.
+ //
+ // +-----------+-------------------+-------------+
+ // | State | Event || Next State |
+ // +-----------+-------------------+-------------+
+ // | IDLE | beginFrame || BEGUN |
+ // | BEGUN | prepareFrame || PREPARED |
+ // | PREPARED | dequeueBuffer [1] || GLES |
+ // | PREPARED | advanceFrame [2] || HWC |
+ // | GLES | queueBuffer || GLES_DONE |
+ // | GLES_DONE | advanceFrame || HWC |
+ // | HWC | onFrameCommitted || IDLE |
+ // +-----------+-------------------++------------+
+ // [1] COMPOSITION_GLES and COMPOSITION_MIXED frames.
+ // [2] COMPOSITION_HWC frames.
+ //
+ enum DbgState {
+ // no buffer dequeued, don't know anything about the next frame
+ DBG_STATE_IDLE,
+ // output buffer dequeued, framebuffer source not yet known
+ DBG_STATE_BEGUN,
+ // output buffer dequeued, framebuffer source known but not provided
+ // to GLES yet.
+ DBG_STATE_PREPARED,
+ // GLES driver has a buffer dequeued
+ DBG_STATE_GLES,
+ // GLES driver has queued the buffer, we haven't sent it to HWC yet
+ DBG_STATE_GLES_DONE,
+ // HWC has the buffer for this frame
+ DBG_STATE_HWC,
+ };
+ DbgState mDbgState;
+ CompositionType mDbgLastCompositionType;
+
+ const char* dbgStateStr() const;
+ static const char* dbgSourceStr(Source s);
+
+ bool mMustRecompose;
+};
+
+// ---------------------------------------------------------------------------
+} // namespace android
+// ---------------------------------------------------------------------------
+
+#endif // ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
+