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-rw-r--r--services/surfaceflinger/Android.mk1
-rw-r--r--services/surfaceflinger/DisplayHardware/BufferQueueInterposer.cpp238
-rw-r--r--services/surfaceflinger/DisplayHardware/BufferQueueInterposer.h152
-rw-r--r--services/surfaceflinger/DisplayHardware/HWComposer.cpp12
-rw-r--r--services/surfaceflinger/DisplayHardware/HWComposer.h2
-rw-r--r--services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp57
-rw-r--r--services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h31
7 files changed, 483 insertions, 10 deletions
diff --git a/services/surfaceflinger/Android.mk b/services/surfaceflinger/Android.mk
index 6f89ffa..30a01be 100644
--- a/services/surfaceflinger/Android.mk
+++ b/services/surfaceflinger/Android.mk
@@ -14,6 +14,7 @@ LOCAL_SRC_FILES:= \
SurfaceFlingerConsumer.cpp \
SurfaceTextureLayer.cpp \
Transform.cpp \
+ DisplayHardware/BufferQueueInterposer.cpp \
DisplayHardware/FramebufferSurface.cpp \
DisplayHardware/HWComposer.cpp \
DisplayHardware/PowerHAL.cpp \
diff --git a/services/surfaceflinger/DisplayHardware/BufferQueueInterposer.cpp b/services/surfaceflinger/DisplayHardware/BufferQueueInterposer.cpp
new file mode 100644
index 0000000..d8ad224
--- /dev/null
+++ b/services/surfaceflinger/DisplayHardware/BufferQueueInterposer.cpp
@@ -0,0 +1,238 @@
+/*
+ * 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.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "BQInterposer"
+
+#include "BufferQueueInterposer.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+#define BQI_LOGV(x, ...) ALOGV("[%s] "x, mName.string(), ##__VA_ARGS__)
+#define BQI_LOGD(x, ...) ALOGD("[%s] "x, mName.string(), ##__VA_ARGS__)
+#define BQI_LOGI(x, ...) ALOGI("[%s] "x, mName.string(), ##__VA_ARGS__)
+#define BQI_LOGW(x, ...) ALOGW("[%s] "x, mName.string(), ##__VA_ARGS__)
+#define BQI_LOGE(x, ...) ALOGE("[%s] "x, mName.string(), ##__VA_ARGS__)
+
+// Get an ID that's unique within this process.
+static int32_t createProcessUniqueId() {
+ static volatile int32_t globalCounter = 0;
+ return android_atomic_inc(&globalCounter);
+}
+
+BufferQueueInterposer::BufferQueueInterposer(
+ const sp<IGraphicBufferProducer>& sink, const String8& name)
+: mSink(sink),
+ mName(name),
+ mAcquired(false)
+{
+ BQI_LOGV("BufferQueueInterposer sink=%p", sink.get());
+
+ // We need one additional dequeued buffer beyond what the source needs.
+ // To have more than one (the default), we must call setBufferCount. But
+ // we have no way of knowing what the sink has set as the minimum buffer
+ // count, so if we just call setBufferCount(3) it may fail (and does, on
+ // one device using a video encoder sink). So far on the devices we care
+ // about, this is the smallest value that works.
+ //
+ // TODO: Change IGraphicBufferProducer and implementations to support this.
+ // Maybe change it so both the consumer and producer declare how many
+ // buffers they need, and the IGBP adds them? Then BQInterposer would just
+ // add 1 to the source's buffer count.
+ mSink->setBufferCount(6);
+}
+
+BufferQueueInterposer::~BufferQueueInterposer() {
+ Mutex::Autolock lock(mMutex);
+ flushQueuedBuffersLocked();
+ BQI_LOGV("~BufferQueueInterposer");
+}
+
+status_t BufferQueueInterposer::requestBuffer(int slot,
+ sp<GraphicBuffer>* outBuf) {
+ BQI_LOGV("requestBuffer slot=%d", slot);
+ Mutex::Autolock lock(mMutex);
+
+ if (size_t(slot) >= mBuffers.size()) {
+ size_t size = mBuffers.size();
+ mBuffers.insertAt(size, size - slot + 1);
+ }
+ sp<GraphicBuffer>& buf = mBuffers.editItemAt(slot);
+
+ status_t result = mSink->requestBuffer(slot, &buf);
+ *outBuf = buf;
+ return result;
+}
+
+status_t BufferQueueInterposer::setBufferCount(int bufferCount) {
+ BQI_LOGV("setBufferCount count=%d", bufferCount);
+ Mutex::Autolock lock(mMutex);
+
+ bufferCount += 1;
+
+ status_t result = flushQueuedBuffersLocked();
+ if (result != NO_ERROR)
+ return result;
+
+ result = mSink->setBufferCount(bufferCount);
+ if (result != NO_ERROR)
+ return result;
+
+ for (size_t i = 0; i < mBuffers.size(); i++)
+ mBuffers.editItemAt(i).clear();
+ ssize_t n = mBuffers.resize(bufferCount);
+ result = (n < 0) ? n : result;
+
+ return result;
+}
+
+status_t BufferQueueInterposer::dequeueBuffer(int* slot, sp<Fence>* fence,
+ uint32_t w, uint32_t h, uint32_t format, uint32_t usage) {
+ BQI_LOGV("dequeueBuffer %ux%u fmt=%u usage=%#x", w, h, format, usage);
+ return mSink->dequeueBuffer(slot, fence, w, h, format, usage);
+}
+
+status_t BufferQueueInterposer::queueBuffer(int slot,
+ const QueueBufferInput& input, QueueBufferOutput* output) {
+ BQI_LOGV("queueBuffer slot=%d", slot);
+ Mutex::Autolock lock(mMutex);
+ mQueue.push(QueuedBuffer(slot, input));
+ *output = mQueueBufferOutput;
+ return NO_ERROR;
+}
+
+void BufferQueueInterposer::cancelBuffer(int slot, const sp<Fence>& fence) {
+ BQI_LOGV("cancelBuffer slot=%d", slot);
+ mSink->cancelBuffer(slot, fence);
+}
+
+int BufferQueueInterposer::query(int what, int* value) {
+ BQI_LOGV("query what=%d", what);
+ return mSink->query(what, value);
+}
+
+status_t BufferQueueInterposer::setSynchronousMode(bool enabled) {
+ BQI_LOGV("setSynchronousMode %s", enabled ? "true" : "false");
+ return mSink->setSynchronousMode(enabled);
+}
+
+status_t BufferQueueInterposer::connect(int api, QueueBufferOutput* output) {
+ BQI_LOGV("connect api=%d", api);
+ Mutex::Autolock lock(mMutex);
+ status_t result = mSink->connect(api, &mQueueBufferOutput);
+ if (result == NO_ERROR) {
+ *output = mQueueBufferOutput;
+ }
+ return result;
+}
+
+status_t BufferQueueInterposer::disconnect(int api) {
+ BQI_LOGV("disconnect: api=%d", api);
+ Mutex::Autolock lock(mMutex);
+ flushQueuedBuffersLocked();
+ return mSink->disconnect(api);
+}
+
+status_t BufferQueueInterposer::pullEmptyBuffer() {
+ status_t result;
+
+ int slot;
+ sp<Fence> fence;
+ result = dequeueBuffer(&slot, &fence, 0, 0, 0, 0);
+ if (result == IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION) {
+ sp<GraphicBuffer> buffer;
+ result = requestBuffer(slot, &buffer);
+ } else if (result != NO_ERROR) {
+ return result;
+ }
+
+ uint32_t w, h, transformHint, numPendingBuffers;
+ mQueueBufferOutput.deflate(&w, &h, &transformHint, &numPendingBuffers);
+
+ IGraphicBufferProducer::QueueBufferInput qbi(0, Rect(w, h),
+ NATIVE_WINDOW_SCALING_MODE_FREEZE, 0, fence);
+ IGraphicBufferProducer::QueueBufferOutput qbo;
+ result = queueBuffer(slot, qbi, &qbo);
+ if (result != NO_ERROR)
+ return result;
+
+ return NO_ERROR;
+}
+
+status_t BufferQueueInterposer::acquireBuffer(sp<GraphicBuffer>* buf,
+ sp<Fence>* fence) {
+ Mutex::Autolock lock(mMutex);
+ if (mQueue.empty()) {
+ BQI_LOGV("acquireBuffer: no buffers available");
+ return NO_BUFFER_AVAILABLE;
+ }
+ if (mAcquired) {
+ BQI_LOGE("acquireBuffer: buffer already acquired");
+ return BUFFER_ALREADY_ACQUIRED;
+ }
+ BQI_LOGV("acquireBuffer: acquiring slot %d", mQueue[0].slot);
+
+ *buf = mBuffers[mQueue[0].slot];
+ *fence = mQueue[0].fence;
+ mAcquired = true;
+ return NO_ERROR;
+}
+
+status_t BufferQueueInterposer::releaseBuffer(const sp<Fence>& fence) {
+ Mutex::Autolock lock(mMutex);
+ if (!mAcquired) {
+ BQI_LOGE("releaseBuffer: releasing a non-acquired buffer");
+ return BUFFER_NOT_ACQUIRED;
+ }
+ BQI_LOGV("releaseBuffer: releasing slot %d to sink", mQueue[0].slot);
+
+ const QueuedBuffer& b = mQueue[0];
+ status_t result = mSink->queueBuffer(b.slot,
+ QueueBufferInput(b.timestamp, b.crop, b.scalingMode,
+ b.transform, b.fence),
+ &mQueueBufferOutput);
+ mQueue.removeAt(0);
+ mAcquired = false;
+
+ return result;
+}
+
+status_t BufferQueueInterposer::flushQueuedBuffersLocked() {
+ if (mAcquired) {
+ BQI_LOGE("flushQueuedBuffersLocked: buffer acquired, can't flush");
+ return INVALID_OPERATION;
+ }
+
+ status_t result = NO_ERROR;
+ for (size_t i = 0; i < mQueue.size(); i++) {
+ const QueuedBuffer& b = mQueue[i];
+ BQI_LOGV("flushing queued slot %d to sink", b.slot);
+ status_t err = mSink->queueBuffer(b.slot,
+ QueueBufferInput(b.timestamp, b.crop, b.scalingMode,
+ b.transform, b.fence),
+ &mQueueBufferOutput);
+ if (err != NO_ERROR && result == NO_ERROR) // latch first error
+ result = err;
+ }
+ mQueue.clear();
+ return result;
+}
+
+// ---------------------------------------------------------------------------
+} // namespace android
+// ---------------------------------------------------------------------------
diff --git a/services/surfaceflinger/DisplayHardware/BufferQueueInterposer.h b/services/surfaceflinger/DisplayHardware/BufferQueueInterposer.h
new file mode 100644
index 0000000..7208630
--- /dev/null
+++ b/services/surfaceflinger/DisplayHardware/BufferQueueInterposer.h
@@ -0,0 +1,152 @@
+/*
+ * 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_BUFFERQUEUEINTERPOSER_H
+#define ANDROID_SF_BUFFERQUEUEINTERPOSER_H
+
+#include <gui/IGraphicBufferProducer.h>
+#include <utils/Mutex.h>
+#include <utils/Vector.h>
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+// BufferQueueInterposers introduce an extra stage between a buffer producer
+// (the source) and a buffer consumer (the sink), which communicate via the
+// IGraphicBufferProducer interface. It is designed to be as transparent as
+// possible to both endpoints, so that they can work the same whether an
+// interposer is present or not.
+//
+// When the interpose is present, the source queues buffers to the
+// IGraphicBufferProducer implemented by BufferQueueInterposer. A client of
+// the BufferQueueInterposer can acquire each buffer in turn and read or
+// modify it, releasing the buffer when finished. When the buffer is released,
+// the BufferQueueInterposer queues it to the original IGraphicBufferProducer
+// interface representing the sink.
+//
+// A BufferQueueInterposer can be used to do additional rendering to a buffer
+// before it is consumed -- essentially pipelining two producers. As an
+// example, SurfaceFlinger uses this to implement mixed GLES and HWC
+// compositing to the same buffer for virtual displays. If it used two separate
+// buffer queues, then in GLES-only or mixed GLES+HWC compositing, the HWC
+// would have to copy the GLES output buffer to the HWC output buffer, using
+// more bandwidth than having HWC do additional composition "in place" on the
+// GLES output buffer.
+//
+// The goal for this class is to be usable in a variety of situations and be
+// part of libgui. But both the interface and implementation need some
+// iteration before then, so for now it should only be used by
+// VirtualDisplaySurface, which is why it's currently in SurfaceFlinger.
+//
+// Some of the problems that still need to be solved are:
+//
+// - Refactor the interposer interface along with BufferQueue and ConsumerBase,
+// so that there is a common interface for the consumer end of a queue. The
+// existing interfaces have some problems when the implementation isn't the
+// final consumer.
+//
+// - The interposer needs at least one buffer in addition to those used by the
+// source and sink. setBufferCount and QueueBufferOutput both need to
+// account for this. It's not possible currently to do this generically,
+// since we can't find out how many buffers the source and sink need. (See
+// the horrible hack in the BufferQueueInterposer constructor).
+//
+// - Abandoning, disconnecting, and connecting need to pass through somehow.
+// There needs to be a way to tell the interposer client to release its
+// buffer immediately so it can be queued/released, e.g. when the source
+// calls disconnect().
+//
+// - Right now the source->BQI queue is synchronous even if the BQI->sink
+// queue is asynchronous. Need to figure out how asynchronous should behave
+// and implement that.
+
+class BufferQueueInterposer : public BnGraphicBufferProducer {
+public:
+ BufferQueueInterposer(const sp<IGraphicBufferProducer>& sink,
+ const String8& name);
+
+ //
+ // IGraphicBufferProducer interface
+ //
+ virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* outBuf);
+ virtual status_t setBufferCount(int bufferCount);
+ virtual status_t dequeueBuffer(int* slot, sp<Fence>* fence,
+ uint32_t w, uint32_t h, uint32_t format, uint32_t usage);
+ virtual status_t queueBuffer(int slot,
+ const QueueBufferInput& input, QueueBufferOutput* output);
+ virtual void cancelBuffer(int slot, const sp<Fence>& fence);
+ virtual int query(int what, int* value);
+ virtual status_t setSynchronousMode(bool enabled);
+ virtual status_t connect(int api, QueueBufferOutput* output);
+ virtual status_t disconnect(int api);
+
+ //
+ // Interposer interface
+ //
+
+ enum {
+ NO_BUFFER_AVAILABLE = 2, // matches BufferQueue
+ BUFFER_NOT_ACQUIRED,
+ BUFFER_ALREADY_ACQUIRED,
+ };
+
+ // Acquire the oldest queued buffer. If no buffers are pending, returns
+ // NO_BUFFER_AVAILABLE. If a buffer is currently acquired, returns
+ // BUFFER_ALREADY_ACQUIRED.
+ status_t acquireBuffer(sp<GraphicBuffer>* buf, sp<Fence>* fence);
+
+ // Release the currently acquired buffer, queueing it to the sink. If the
+ // current buffer hasn't been acquired, returns BUFFER_NOT_ACQUIRED.
+ status_t releaseBuffer(const sp<Fence>& fence);
+
+ // pullEmptyBuffer dequeues a buffer from the sink, then immediately
+ // queues it to the interposer. This makes a buffer available for the
+ // client to acquire even if the source hasn't queued one.
+ status_t pullEmptyBuffer();
+
+private:
+ struct QueuedBuffer {
+ QueuedBuffer(): slot(-1) {}
+ QueuedBuffer(int slot, const QueueBufferInput& qbi): slot(slot) {
+ qbi.deflate(&timestamp, &crop, &scalingMode, &transform, &fence);
+ }
+ int slot;
+ int64_t timestamp;
+ Rect crop;
+ int scalingMode;
+ uint32_t transform;
+ sp<Fence> fence;
+ };
+
+ virtual ~BufferQueueInterposer();
+ status_t flushQueuedBuffersLocked();
+
+ const sp<IGraphicBufferProducer> mSink;
+ String8 mName;
+
+ Mutex mMutex;
+ Vector<sp<GraphicBuffer> > mBuffers;
+ Vector<QueuedBuffer> mQueue;
+ bool mAcquired;
+ QueueBufferOutput mQueueBufferOutput;
+};
+
+// ---------------------------------------------------------------------------
+} // namespace android
+// ---------------------------------------------------------------------------
+
+#endif // ANDROID_SF_BUFFERQUEUEINTERPOSER_H
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index 4b6c413..eeb1fef 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -655,6 +655,18 @@ status_t HWComposer::commit() {
mLists[0]->sur = eglGetCurrentSurface(EGL_DRAW);
}
+ // For virtual displays, the framebufferTarget buffer also serves as
+ // the HWC output buffer, so we need to copy the buffer handle and
+ // dup() the acquire fence.
+ for (size_t i=HWC_NUM_DISPLAY_TYPES; i<mNumDisplays; i++) {
+ DisplayData& disp(mDisplayData[i]);
+ if (disp.framebufferTarget) {
+ mLists[i]->outbuf = disp.framebufferTarget->handle;
+ mLists[i]->outbufAcquireFenceFd =
+ dup(disp.framebufferTarget->acquireFenceFd);
+ }
+ }
+
err = mHwc->set(mHwc, mNumDisplays, mLists);
for (size_t i=0 ; i<mNumDisplays ; i++) {
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index 9816a45..92e4cbf 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -112,7 +112,7 @@ public:
// does this display have layers handled by GLES
bool hasGlesComposition(int32_t id) const;
- // get the releaseFence file descriptor for the given display
+ // get the releaseFence file descriptor for a display's framebuffer layer.
// the release fence is only valid after commit()
int getAndResetReleaseFenceFd(int32_t id);
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
index d30e9bf..433e1eb 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
@@ -14,8 +14,8 @@
* limitations under the License.
*/
-#include <gui/IGraphicBufferProducer.h>
#include "VirtualDisplaySurface.h"
+#include "HWComposer.h"
// ---------------------------------------------------------------------------
namespace android {
@@ -25,15 +25,22 @@ VirtualDisplaySurface::VirtualDisplaySurface(HWComposer& hwc, int disp,
const sp<IGraphicBufferProducer>& sink, const String8& name)
: mHwc(hwc),
mDisplayId(disp),
- mSink(sink),
- mName(name)
+ mSource(new BufferQueueInterposer(sink, name)),
+ mName(name),
+ mReleaseFence(Fence::NO_FENCE)
{}
VirtualDisplaySurface::~VirtualDisplaySurface() {
+ if (mAcquiredBuffer != NULL) {
+ status_t result = mSource->releaseBuffer(mReleaseFence);
+ ALOGE_IF(result != NO_ERROR, "VirtualDisplaySurface \"%s\": "
+ "failed to release previous buffer: %d",
+ mName.string(), result);
+ }
}
sp<IGraphicBufferProducer> VirtualDisplaySurface::getIGraphicBufferProducer() const {
- return mSink;
+ return mSource;
}
status_t VirtualDisplaySurface::compositionComplete() {
@@ -41,13 +48,49 @@ status_t VirtualDisplaySurface::compositionComplete() {
}
status_t VirtualDisplaySurface::advanceFrame() {
- return NO_ERROR;
+ Mutex::Autolock lock(mMutex);
+ status_t result = NO_ERROR;
+
+ if (mAcquiredBuffer != NULL) {
+ result = mSource->releaseBuffer(mReleaseFence);
+ ALOGE_IF(result != NO_ERROR, "VirtualDisplaySurface \"%s\": "
+ "failed to release previous buffer: %d",
+ mName.string(), result);
+ mAcquiredBuffer.clear();
+ mReleaseFence = Fence::NO_FENCE;
+ }
+
+ sp<Fence> fence;
+ result = mSource->acquireBuffer(&mAcquiredBuffer, &fence);
+ if (result == BufferQueueInterposer::NO_BUFFER_AVAILABLE) {
+ result = mSource->pullEmptyBuffer();
+ if (result != NO_ERROR)
+ return result;
+ result = mSource->acquireBuffer(&mAcquiredBuffer, &fence);
+ }
+ if (result != NO_ERROR)
+ return result;
+
+ return mHwc.fbPost(mDisplayId, fence, mAcquiredBuffer);
}
status_t VirtualDisplaySurface::setReleaseFenceFd(int fenceFd) {
if (fenceFd >= 0) {
- ALOGW("[%s] unexpected release fence", mName.string());
- close(fenceFd);
+ sp<Fence> fence(new Fence(fenceFd));
+ Mutex::Autolock lock(mMutex);
+ sp<Fence> mergedFence = Fence::merge(
+ String8::format("VirtualDisplaySurface \"%s\"",
+ mName.string()),
+ mReleaseFence, fence);
+ if (!mergedFence->isValid()) {
+ ALOGE("VirtualDisplaySurface \"%s\": failed to merge release fence",
+ mName.string());
+ // synchronization is broken, the best we can do is hope fences
+ // signal in order so the new fence will act like a union
+ mReleaseFence = fence;
+ return BAD_VALUE;
+ }
+ mReleaseFence = mergedFence;
}
return NO_ERROR;
}
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
index db886ed..66f8580 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
@@ -17,7 +17,7 @@
#ifndef ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
#define ANDROID_SF_VIRTUAL_DISPLAY_SURFACE_H
-#include <utils/String8.h>
+#include "BufferQueueInterposer.h"
#include "DisplaySurface.h"
// ---------------------------------------------------------------------------
@@ -26,6 +26,28 @@ namespace android {
class HWComposer;
+/* This DisplaySurface implementation uses a BufferQueueInterposer to pass
+ * partially- or fully-composited buffers from the OpenGL ES driver to
+ * HWComposer to use as the output buffer for virtual displays. Allowing HWC
+ * to compose into the same buffer that contains GLES results saves bandwidth
+ * compared to having two separate BufferQueues for frames with at least some
+ * GLES composition.
+ *
+ * The alternative would be to have two complete BufferQueues, one from GLES
+ * to HWC and one from HWC to the virtual display sink (e.g. video encoder).
+ * For GLES-only frames, the same bandwidth saving could be achieved if buffers
+ * could be acquired from the GLES->HWC queue and inserted into the HWC->sink
+ * queue. That would be complicated and doesn't help the mixed GLES+HWC case.
+ *
+ * On frames with no GLES composition, the VirtualDisplaySurface dequeues a
+ * buffer directly from the sink IGraphicBufferProducer and passes it to HWC,
+ * bypassing the GLES driver. This is only guaranteed to work if
+ * eglSwapBuffers doesn't immediately dequeue a buffer for the next frame,
+ * since we can't rely on being able to dequeue more than one buffer at a time.
+ *
+ * TODO(jessehall): Add a libgui test that ensures that EGL/GLES do lazy
+ * dequeBuffers; we've wanted to require that for other reasons anyway.
+ */
class VirtualDisplaySurface : public DisplaySurface {
public:
VirtualDisplaySurface(HWComposer& hwc, int disp,
@@ -45,8 +67,13 @@ private:
// immutable after construction
HWComposer& mHwc;
int mDisplayId;
- sp<IGraphicBufferProducer> mSink;
+ sp<BufferQueueInterposer> mSource;
String8 mName;
+
+ // mutable, must be synchronized with mMutex
+ Mutex mMutex;
+ sp<GraphicBuffer> mAcquiredBuffer;
+ sp<Fence> mReleaseFence;
};
// ---------------------------------------------------------------------------