libhwc2.1: Skip redundant onRefresh in histogramSample

DPU driver maintains always-on histogram engine state with up to
date histogram data. Therefore we don't have explicitly to trigger
onRefresh in case histogram configuration does not change.

Test: aidl_hist_client 500 500 1000 1999 340 340 344 POST 1000000
Bug: 261376040
Change-Id: I44824ee836adb66aeb214c371a11ed350d13b069
Signed-off-by: Leo Chen <yinchiuan@google.com>

3 files changed, 53 insertions, 6 deletions

diff --git a/libhwc2.1/histogram_mediator.cpp b/libhwc2.1/histogram_mediator.cpp
index d1fba54..f23feec 100644
--- a/libhwc2.1/histogram_mediator.cpp
+++ b/libhwc2.1/histogram_mediator.cpp
@@ -60,7 +60,7 @@ histogram::HistogramErrorCode histogram::HistogramMediator::requestHist() {
         std::unique_lock<std::mutex> lk(mIDLHistogram->mDataCollectingMutex);
         if (moduleDisplayInterface->setHistogramControl(
                 hidl_histogram_control_t::HISTOGRAM_CONTROL_REQUEST) != NO_ERROR) {
-                return histogram::HistogramErrorCode::ENABLE_HIST_ERROR;
+            return histogram::HistogramErrorCode::ENABLE_HIST_ERROR;
         }
         mIDLHistogram->mHistReq_pending = true;
     }
diff --git a/libhwc2.1/histogram_mediator.h b/libhwc2.1/histogram_mediator.h
index fa81e0b..54d28c9 100644
--- a/libhwc2.1/histogram_mediator.h
+++ b/libhwc2.1/histogram_mediator.h
@@ -73,10 +73,38 @@ public:
         bool mHistReq_pending = false;
         std::mutex mDataCollectingMutex; // for data collecting operations
     };
+
+    struct HistogramConfig {
+        RoiRect mRoi;
+        Weight mWeights;
+        HistogramPos mPos;
+
+        HistogramConfig() {}
+
+        HistogramConfig(const RoiRect &roi, const Weight &weights, const HistogramPos &pos) {
+            mRoi = roi;
+            mWeights = weights;
+            mPos = pos;
+        }
+
+        bool operator!=(const HistogramConfig &rhs) {
+            return mRoi != rhs.mRoi || mWeights != rhs.mWeights || mPos != rhs.mPos;
+        }
+
+        HistogramConfig &operator=(const HistogramConfig &rhs) {
+            mRoi = rhs.mRoi;
+            mWeights = rhs.mWeights;
+            mPos = rhs.mPos;
+            return *this;
+        }
+    };
+
     uint32_t getFrameCount();
     void setSampleFrameCounter(int32_t id) { mSampledFrameCounter = id; }
     uint32_t getSampleFrameCounter() { return mSampledFrameCounter; }
     bool histRequested() { return mIDLHistogram->mHistReq_pending; }
+    std::mutex mConfigMutex;
+    HistogramConfig mConfig GUARDED_BY(mConfigMutex);
 
 private:
     int calculateThreshold(const RoiRect &roi);
diff --git a/libhwc2.1/pixel-display.cpp b/libhwc2.1/pixel-display.cpp
index fec7309..366945a 100644
--- a/libhwc2.1/pixel-display.cpp
+++ b/libhwc2.1/pixel-display.cpp
@@ -201,17 +201,36 @@ ndk::ScopedAStatus Display::setRefreshRateThrottle(int delayMs, int *_aidl_retur
 
 bool Display::runMediator(const RoiRect &roi, const Weight &weight, const HistogramPos &pos,
                             std::vector<char16_t> *histogrambuffer) {
-    if (mMediator.setRoiWeightThreshold(roi, weight, pos) != HistogramErrorCode::NONE) {
-        ALOGE("histogram error, SET_ROI_WEIGHT_THRESHOLD ERROR\n");
-        return false;
+    bool isConfigChanged;
+    histogram::HistogramMediator::HistogramConfig pendingConfig(roi, weight, pos);
+
+    {
+        std::unique_lock<std::mutex> lk(mMediator.mConfigMutex);
+        isConfigChanged = mMediator.mConfig != pendingConfig;
+
+        if (isConfigChanged &&
+            mMediator.setRoiWeightThreshold(roi, weight, pos) != HistogramErrorCode::NONE) {
+            ALOGE("histogram error, SET_ROI_WEIGHT_THRESHOLD ERROR\n");
+            return false;
+        }
+
+        mMediator.mConfig = pendingConfig;
     }
+
     if (!mMediator.histRequested() &&
         mMediator.requestHist() == HistogramErrorCode::ENABLE_HIST_ERROR) {
         ALOGE("histogram error, ENABLE_HIST ERROR\n");
     }
-    if (mMediator.getFrameCount() != mMediator.getSampleFrameCounter()) {
-        mDisplay->mDevice->onRefresh(mDisplay->mDisplayId); // DRM not busy & sampled frame changed
+
+    /*
+     * DPU driver maintains always-on histogram engine state with up to date histogram data.
+     * Therefore we don't have explicitly to trigger onRefresh in case histogram configuration
+     * does not change.
+     */
+    if (isConfigChanged) {
+        mDisplay->mDevice->onRefresh(mDisplay->mDisplayId);
     }
+
     if (mMediator.collectRoiLuma(histogrambuffer) != HistogramErrorCode::NONE) {
         ALOGE("histogram error, COLLECT_ROI_LUMA ERROR\n");
         return false;