camera: Drop pending preview for enableZsl shots

If the device support ZSL, drop pending preview buffers to reduce
the chance the rendering preview frames newer than the still frame
during takePicture().

Test: CTS
Bug: 67497723
Change-Id: I5f253a402a6302d31777ad4ca2878ef0d0d1ae44
Merged-In: I5f253a402a6302d31777ad4ca2878ef0d0d1ae44
(cherry picked from commit 63068520622543b57c8607612a4f44fbbef6a021)

10 files changed, 77 insertions, 2 deletions

diff --git a/services/camera/libcameraservice/api1/Camera2Client.cpp b/services/camera/libcameraservice/api1/Camera2Client.cpp
index 2cf648f111..585d2ebd5f 100644
--- a/services/camera/libcameraservice/api1/Camera2Client.cpp
+++ b/services/camera/libcameraservice/api1/Camera2Client.cpp
@@ -859,6 +859,12 @@ status_t Camera2Client::startPreviewL(Parameters &params, bool restart) {
 
     outputStreams.push(getPreviewStreamId());
 
+    if (params.isDeviceZslSupported) {
+        // If device ZSL is supported, resume preview buffers that may be paused
+        // during last takePicture().
+        mDevice->dropStreamBuffers(false, getPreviewStreamId());
+    }
+
     if (!params.recordingHint) {
         if (!restart) {
             res = mStreamingProcessor->updatePreviewRequest(params);
diff --git a/services/camera/libcameraservice/api1/client2/CaptureSequencer.cpp b/services/camera/libcameraservice/api1/client2/CaptureSequencer.cpp
index b65f1c76ca..1ee216fd9a 100644
--- a/services/camera/libcameraservice/api1/client2/CaptureSequencer.cpp
+++ b/services/camera/libcameraservice/api1/client2/CaptureSequencer.cpp
@@ -553,6 +553,12 @@ CaptureSequencer::CaptureState CaptureSequencer::manageStandardCapture(
         return DONE;
     }
 
+    if (l.mParameters.isDeviceZslSupported) {
+        // If device ZSL is supported, drop all pending preview buffers to reduce the chance of
+        // rendering preview frames newer than the still frame.
+        client->getCameraDevice()->dropStreamBuffers(true, client->getPreviewStreamId());
+    }
+
     /**
      * Clear the streaming request for still-capture pictures
      *   (as opposed to i.e. video snapshots)
diff --git a/services/camera/libcameraservice/common/CameraDeviceBase.h b/services/camera/libcameraservice/common/CameraDeviceBase.h
index 3919bfa7c8..a90050e1bf 100644
--- a/services/camera/libcameraservice/common/CameraDeviceBase.h
+++ b/services/camera/libcameraservice/common/CameraDeviceBase.h
@@ -349,6 +349,11 @@ class CameraDeviceBase : public virtual RefBase {
     virtual status_t setConsumerSurfaces(int streamId,
             const std::vector<sp<Surface>>& consumers) = 0;
 
+    /**
+     * Drop buffers for stream of streamId if dropping is true. If dropping is false, do not
+     * drop buffers for stream of streamId.
+     */
+    virtual status_t dropStreamBuffers(bool /*dropping*/, int /*streamId*/) = 0;
 };
 
 }; // namespace android
diff --git a/services/camera/libcameraservice/device3/Camera3Device.cpp b/services/camera/libcameraservice/device3/Camera3Device.cpp
index ced1d3af42..a980cde235 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.cpp
+++ b/services/camera/libcameraservice/device3/Camera3Device.cpp
@@ -1977,6 +1977,20 @@ status_t Camera3Device::setConsumerSurfaces(int streamId,
     return OK;
 }
 
+status_t Camera3Device::dropStreamBuffers(bool dropping, int streamId) {
+    Mutex::Autolock il(mInterfaceLock);
+    Mutex::Autolock l(mLock);
+
+    int idx = mOutputStreams.indexOfKey(streamId);
+    if (idx == NAME_NOT_FOUND) {
+        ALOGE("%s: Stream %d is not found.", __FUNCTION__, streamId);
+        return BAD_VALUE;
+    }
+
+    sp<Camera3OutputStreamInterface> stream = mOutputStreams.editValueAt(idx);
+    return stream->dropBuffers(dropping);
+}
+
 /**
  * Camera3Device private methods
  */
diff --git a/services/camera/libcameraservice/device3/Camera3Device.h b/services/camera/libcameraservice/device3/Camera3Device.h
index fbbbd08ce9..081af1978b 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.h
+++ b/services/camera/libcameraservice/device3/Camera3Device.h
@@ -178,6 +178,12 @@ class Camera3Device :
      */
     status_t setConsumerSurfaces(int streamId, const std::vector<sp<Surface>>& consumers) override;
 
+    /**
+     * Drop buffers for stream of streamId if dropping is true. If dropping is false, do not
+     * drop buffers for stream of streamId.
+     */
+    status_t dropStreamBuffers(bool dropping, int streamId) override;
+
   private:
 
     // internal typedefs
diff --git a/services/camera/libcameraservice/device3/Camera3DummyStream.cpp b/services/camera/libcameraservice/device3/Camera3DummyStream.cpp
index 6e2978f164..84fb8909d8 100644
--- a/services/camera/libcameraservice/device3/Camera3DummyStream.cpp
+++ b/services/camera/libcameraservice/device3/Camera3DummyStream.cpp
@@ -108,6 +108,10 @@ bool Camera3DummyStream::isConsumerConfigurationDeferred(size_t /*surface_id*/)
     return false;
 }
 
+status_t Camera3DummyStream::dropBuffers(bool /*dropping*/) {
+    return OK;
+}
+
 status_t Camera3DummyStream::setConsumers(const std::vector<sp<Surface>>& /*consumers*/) {
     ALOGE("%s: Stream %d: Dummy stream doesn't support set consumer surface!",
             __FUNCTION__, mId);
diff --git a/services/camera/libcameraservice/device3/Camera3DummyStream.h b/services/camera/libcameraservice/device3/Camera3DummyStream.h
index 492fb49eb1..9710765c2a 100644
--- a/services/camera/libcameraservice/device3/Camera3DummyStream.h
+++ b/services/camera/libcameraservice/device3/Camera3DummyStream.h
@@ -57,6 +57,12 @@ class Camera3DummyStream :
     virtual status_t detachBuffer(sp<GraphicBuffer>* buffer, int* fenceFd);
 
     /**
+     * Drop buffers for stream of streamId if dropping is true. If dropping is false, do not
+     * drop buffers for stream of streamId.
+     */
+    virtual status_t dropBuffers(bool /*dropping*/) override;
+
+    /**
      * Return if this output stream is for video encoding.
      */
     bool isVideoStream() const;
diff --git a/services/camera/libcameraservice/device3/Camera3OutputStream.cpp b/services/camera/libcameraservice/device3/Camera3OutputStream.cpp
index dcaefe374e..8460c34d00 100644
--- a/services/camera/libcameraservice/device3/Camera3OutputStream.cpp
+++ b/services/camera/libcameraservice/device3/Camera3OutputStream.cpp
@@ -44,6 +44,7 @@ Camera3OutputStream::Camera3OutputStream(int id,
         mUseBufferManager(false),
         mTimestampOffset(timestampOffset),
         mConsumerUsage(0),
+        mDropBuffers(false),
         mDequeueBufferLatency(kDequeueLatencyBinSize) {
 
     if (mConsumer == NULL) {
@@ -70,6 +71,7 @@ Camera3OutputStream::Camera3OutputStream(int id,
         mUseBufferManager(false),
         mTimestampOffset(timestampOffset),
         mConsumerUsage(0),
+        mDropBuffers(false),
         mDequeueBufferLatency(kDequeueLatencyBinSize) {
 
     if (format != HAL_PIXEL_FORMAT_BLOB && format != HAL_PIXEL_FORMAT_RAW_OPAQUE) {
@@ -100,6 +102,7 @@ Camera3OutputStream::Camera3OutputStream(int id,
         mUseBufferManager(false),
         mTimestampOffset(timestampOffset),
         mConsumerUsage(consumerUsage),
+        mDropBuffers(false),
         mDequeueBufferLatency(kDequeueLatencyBinSize) {
     // Deferred consumer only support preview surface format now.
     if (format != HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED) {
@@ -139,6 +142,7 @@ Camera3OutputStream::Camera3OutputStream(int id, camera3_stream_type_t type,
         mUseBufferManager(false),
         mTimestampOffset(timestampOffset),
         mConsumerUsage(consumerUsage),
+        mDropBuffers(false),
         mDequeueBufferLatency(kDequeueLatencyBinSize) {
 
     if (setId > CAMERA3_STREAM_SET_ID_INVALID) {
@@ -227,9 +231,14 @@ status_t Camera3OutputStream::returnBufferCheckedLocked(
     /**
      * Return buffer back to ANativeWindow
      */
-    if (buffer.status == CAMERA3_BUFFER_STATUS_ERROR) {
+    if (buffer.status == CAMERA3_BUFFER_STATUS_ERROR || mDropBuffers) {
         // Cancel buffer
-        ALOGW("A frame is dropped for stream %d", mId);
+        if (mDropBuffers) {
+            ALOGV("%s: Dropping a frame for stream %d.", __FUNCTION__, mId);
+        } else {
+            ALOGW("%s: A frame is dropped for stream %d due to buffer error.", __FUNCTION__, mId);
+        }
+
         res = currentConsumer->cancelBuffer(currentConsumer.get(),
                 anwBuffer,
                 anwReleaseFence);
@@ -777,6 +786,12 @@ status_t Camera3OutputStream::detachBufferLocked(sp<GraphicBuffer>* buffer, int*
     return res;
 }
 
+status_t Camera3OutputStream::dropBuffers(bool dropping) {
+    Mutex::Autolock l(mLock);
+    mDropBuffers = dropping;
+    return OK;
+}
+
 status_t Camera3OutputStream::notifyBufferReleased(ANativeWindowBuffer* /*anwBuffer*/) {
     return OK;
 }
diff --git a/services/camera/libcameraservice/device3/Camera3OutputStream.h b/services/camera/libcameraservice/device3/Camera3OutputStream.h
index 7023d5d623..4865be7d31 100644
--- a/services/camera/libcameraservice/device3/Camera3OutputStream.h
+++ b/services/camera/libcameraservice/device3/Camera3OutputStream.h
@@ -166,6 +166,11 @@ class Camera3OutputStream :
     virtual status_t notifyBufferReleased(ANativeWindowBuffer *anwBuffer);
 
     /**
+     * Drop buffers if dropping is true. If dropping is false, do not drop buffers.
+     */
+    virtual status_t dropBuffers(bool dropping) override;
+
+    /**
      * Set the graphic buffer manager to get/return the stream buffers.
      *
      * It is only legal to call this method when stream is in STATE_CONSTRUCTED state.
@@ -247,6 +252,9 @@ class Camera3OutputStream :
      */
     uint64_t    mConsumerUsage;
 
+    // Whether to drop valid buffers.
+    bool mDropBuffers;
+
     /**
      * Internal Camera3Stream interface
      */
diff --git a/services/camera/libcameraservice/device3/Camera3OutputStreamInterface.h b/services/camera/libcameraservice/device3/Camera3OutputStreamInterface.h
index 8107dd02b0..1719d74a1c 100644
--- a/services/camera/libcameraservice/device3/Camera3OutputStreamInterface.h
+++ b/services/camera/libcameraservice/device3/Camera3OutputStreamInterface.h
@@ -59,6 +59,11 @@ class Camera3OutputStreamInterface : public virtual Camera3StreamInterface {
      *
      */
     virtual status_t detachBuffer(sp<GraphicBuffer>* buffer, int* fenceFd) = 0;
+
+    /**
+     * Drop buffers if dropping is true. If dropping is false, do not drop buffers.
+     */
+    virtual status_t dropBuffers(bool /*dropping*/) = 0;
 };
 
 } // namespace camera3