libhwc2.1: sync ghbm/dbv and buffer for brightness jump

For mixed composition, if brightness mipi commands and frame are not
synchronized, there will be a dark or white flash when there is a
brightness jump. It happens when HDR become visible or gone and the
brightness animation is disabled.

Bug: 220962789
Change-Id: I2993562a2c69351f561f932305f88bfb4a2b3cf1

5 files changed, 53 insertions, 3 deletions

diff --git a/libhwc2.1/libdevice/BrightnessController.cpp b/libhwc2.1/libdevice/BrightnessController.cpp
index 40fb813..354de59 100644
--- a/libhwc2.1/libdevice/BrightnessController.cpp
+++ b/libhwc2.1/libdevice/BrightnessController.cpp
@@ -133,6 +133,7 @@ void BrightnessController::initBrightnessTable(const DrmDevice& drmDevice,
 
     // init to min before SF sets the brightness
     mDisplayWhitePointNits = cap->normal.nits.min;
+    mPrevDisplayWhitePointNits = mDisplayWhitePointNits;
     mBrightnessIntfSupported = true;
 
     drmModeFreePropertyBlob(blob);
@@ -348,6 +349,8 @@ void BrightnessController::onClearDisplay() {
     mInstantHbmReq.reset(false);
 
     mBrightnessLevel.reset(0);
+    mDisplayWhitePointNits = 0;
+    mPrevDisplayWhitePointNits = 0;
     mGhbm.reset(HbmMode::OFF);
     mDimming.reset(false);
     mHbmDimming = false;
@@ -362,6 +365,7 @@ void BrightnessController::onClearDisplay() {
 int BrightnessController::prepareFrameCommit(ExynosDisplay& display,
                               const DrmConnector& connector,
                               ExynosDisplayDrmInterface::DrmModeAtomicReq& drmReq,
+                              const bool mixedComposition,
                               bool& ghbmSync, bool& lhbmSync, bool& blSync) {
     int ret;
 
@@ -372,6 +376,17 @@ int BrightnessController::prepareFrameCommit(ExynosDisplay& display,
     ATRACE_CALL();
     std::lock_guard<std::recursive_mutex> lock(mBrightnessMutex);
 
+    bool sync = false;
+    if (mixedComposition && mPrevDisplayWhitePointNits > 0 && mDisplayWhitePointNits > 0) {
+        float diff = std::abs(mPrevDisplayWhitePointNits - mDisplayWhitePointNits);
+        float min = std::min(mPrevDisplayWhitePointNits, mDisplayWhitePointNits);
+        if (diff / min > kBrightnessSyncThreshold) {
+            sync = true;
+            ALOGD("%s: enable brightness sync for change from %f to %f", __func__,
+                  mPrevDisplayWhitePointNits, mDisplayWhitePointNits);
+        }
+    }
+
     if (mDimming.is_dirty()) {
         if ((ret = drmReq.atomicAddProperty(connector.id(), connector.dimming_on(),
                                             mDimming.get())) < 0) {
@@ -437,9 +452,11 @@ int BrightnessController::prepareFrameCommit(ExynosDisplay& display,
             } else {
                 mUncheckedBlRequest = true;
                 mPendingBl = mBrightnessLevel.get();
+                blSync = sync;
             }
         }
         mBrightnessLevel.clear_dirty();
+        mPrevDisplayWhitePointNits = mDisplayWhitePointNits;
     }
 
     if (mGhbm.is_dirty() && mGhbmSupported) {
@@ -455,7 +472,7 @@ int BrightnessController::prepareFrameCommit(ExynosDisplay& display,
                                             hbmEnum)) < 0) {
             ALOGE("%s: Fail to set hbm_mode property", __func__);
         } else {
-            ghbmSync = true;
+            ghbmSync = sync;
         }
         mGhbm.clear_dirty();
     }
@@ -705,6 +722,7 @@ int BrightnessController::applyBrightnessViaSysfs(uint32_t level) {
         {
             std::lock_guard<std::recursive_mutex> lock(mBrightnessMutex);
             mBrightnessLevel.reset(level);
+            mPrevDisplayWhitePointNits = mDisplayWhitePointNits;
             ALOGI("level=%d, DimmingOn=%d, Hbm=%d, LhbmOn=%d", level,
                   mDimming.get(), mGhbm.get(), mLhbm.get());
         }
@@ -765,6 +783,7 @@ void BrightnessController::dump(String8& result) {
                         mPendingGhbmStatus.load());
     result.appendFormat("\tdimming usage %d, hbm dimming %d, time us %d\n", mBrightnessDimmingUsage,
                         mHbmDimming, mHbmDimmingTimeUs);
-    result.appendFormat("\twhite point nits %f\n", mDisplayWhitePointNits);
+    result.appendFormat("\twhite point nits current %f, previous %f\n", mDisplayWhitePointNits,
+                        mPrevDisplayWhitePointNits);
     result.appendFormat("\n");
 }
diff --git a/libhwc2.1/libdevice/BrightnessController.h b/libhwc2.1/libdevice/BrightnessController.h
index 3a7fa85..254a576 100644
--- a/libhwc2.1/libdevice/BrightnessController.h
+++ b/libhwc2.1/libdevice/BrightnessController.h
@@ -97,6 +97,7 @@ public:
     int prepareFrameCommit(ExynosDisplay& display,
                            const DrmConnector& connector,
                            ExynosDisplayDrmInterface::DrmModeAtomicReq& drmReq,
+                           const bool mixedComposition,
                            bool& ghbmSync, bool& lhbmSync, bool& blSync);
 
     bool isGhbmSupported() { return mGhbmSupported; }
@@ -177,6 +178,12 @@ public:
     };
 
 private:
+    // sync brightness change for mixed composition when there is more than 50% luminance change.
+    // The percentage is calculated as:
+    //        (big_lumi - small_lumi) / small_lumi
+    // For mixed composition, if remove brightness animations, the minimum brightness jump is
+    // between nbm peak and hbm peak. 50% will cover known panels
+    static constexpr float kBrightnessSyncThreshold = 0.5f;
     // Worst case for panel with brightness range 2 nits to 1000 nits.
     static constexpr float kGhbmMinDimRatio = 0.002;
     static constexpr int32_t kHbmDimmingTimeUs = 5000000;
@@ -254,6 +261,7 @@ private:
 
     // Note IRC or dimming is not in consideration for now.
     float mDisplayWhitePointNits = 0;
+    float mPrevDisplayWhitePointNits = 0;
 
     std::function<void(void)> mUpdateDcLhbm;
 };
diff --git a/libhwc2.1/libdevice/ExynosDisplay.cpp b/libhwc2.1/libdevice/ExynosDisplay.cpp
index 7d01650..d27a8a6 100644
--- a/libhwc2.1/libdevice/ExynosDisplay.cpp
+++ b/libhwc2.1/libdevice/ExynosDisplay.cpp
@@ -3369,6 +3369,7 @@ int32_t ExynosDisplay::presentDisplay(int32_t* outRetireFence) {
     ATRACE_CALL();
     gettimeofday(&updateTimeInfo.lastPresentTime, NULL);
 
+    const bool mixedComposition = isMixedComposition();
     // store this once here for the whole frame so it's consistent
     mUsePowerHints = usePowerHintSession();
     if (mUsePowerHints) {
@@ -3693,6 +3694,8 @@ int32_t ExynosDisplay::presentDisplay(int32_t* outRetireFence) {
         mPowerHalHint.signalActualWorkDuration(duration + mValidationDuration.value_or(0));
     }
 
+    mPriorFrameMixedComposition = mixedComposition;
+
     return ret;
 err:
     printDebugInfos(errString);
@@ -6016,3 +6019,12 @@ int32_t ExynosDisplay::setDebugRCDLayerEnabled(bool enable) {
 int32_t ExynosDisplay::getDisplayIdleTimerSupport(bool &outSupport) {
     return mDisplayInterface->getDisplayIdleTimerSupport(outSupport);
 }
+
+bool ExynosDisplay::isMixedComposition() {
+    for (size_t i = 0; i < mLayers.size(); i++) {
+        if (mLayers[i]->mBrightness < 1.0) {
+            return true;
+        }
+    }
+    return false;
+}
diff --git a/libhwc2.1/libdevice/ExynosDisplay.h b/libhwc2.1/libdevice/ExynosDisplay.h
index d784aa4..b75cc98 100644
--- a/libhwc2.1/libdevice/ExynosDisplay.h
+++ b/libhwc2.1/libdevice/ExynosDisplay.h
@@ -1250,6 +1250,10 @@ class ExynosDisplay {
                     (mVsyncPeriod == mMinDisplayVsyncPeriod));
         }
 
+        // check if there are any dimmed layers
+        bool isMixedComposition();
+        bool isPriorFrameMixedCompostion() { return mPriorFrameMixedComposition; }
+
     private:
         bool skipStaticLayerChanged(ExynosCompositionInfo& compositionInfo);
 
@@ -1267,6 +1271,10 @@ class ExynosDisplay {
         // vsync period of peak refresh rate
         uint32_t mMinDisplayVsyncPeriod;
 
+        // track if the last frame is a mixed composition, to detect mixed
+        // composition to non-mixed composition transition.
+        bool mPriorFrameMixedComposition;
+
         /* Display hint to notify power hal */
         class PowerHalHintWorker : public Worker {
         public:
diff --git a/libhwc2.1/libdisplayinterface/ExynosDisplayDrmInterface.cpp b/libhwc2.1/libdisplayinterface/ExynosDisplayDrmInterface.cpp
index d03b5b7..51dddd7 100644
--- a/libhwc2.1/libdisplayinterface/ExynosDisplayDrmInterface.cpp
+++ b/libhwc2.1/libdisplayinterface/ExynosDisplayDrmInterface.cpp
@@ -1779,8 +1779,11 @@ int32_t ExynosDisplayDrmInterface::deliverWinConfigData()
 
     if (mExynosDisplay->mBrightnessController) {
         bool ghbmSync, lhbmSync, blSync;
+        bool mixedComposition = mExynosDisplay->isMixedComposition()
+                                || mExynosDisplay->isPriorFrameMixedCompostion();
         ret = mExynosDisplay->mBrightnessController->prepareFrameCommit(*mExynosDisplay,
-                                        *mDrmConnector, drmReq, ghbmSync, lhbmSync, blSync);
+                                        *mDrmConnector, drmReq, mixedComposition,
+                                        ghbmSync, lhbmSync, blSync);
         if (ret < 0) {
             HWC_LOGE(mExynosDisplay, "%s: Fail to config brightness", __func__);
         } else {