Merge "Add more unit test for bufferhub"
diff --git a/libs/ui/Android.bp b/libs/ui/Android.bp
index a610a51..102964f 100644
--- a/libs/ui/Android.bp
+++ b/libs/ui/Android.bp
@@ -118,4 +118,7 @@
     vendor_available: true,
 }
 
-subdirs = ["tests"]
+subdirs = [
+    "tests",
+    "tools",
+]
diff --git a/services/surfaceflinger/DisplayHardware/ComposerHal.cpp b/services/surfaceflinger/DisplayHardware/ComposerHal.cpp
index 7d6d988..c707e3c 100644
--- a/services/surfaceflinger/DisplayHardware/ComposerHal.cpp
+++ b/services/surfaceflinger/DisplayHardware/ComposerHal.cpp
@@ -223,6 +223,10 @@
     mWriter.reset();
 }
 
+Error Composer::executeCommands() {
+    return execute();
+}
+
 uint32_t Composer::getMaxVirtualDisplayCount()
 {
     auto ret = mClient->getMaxVirtualDisplayCount();
@@ -750,6 +754,11 @@
         }
     }
 
+    if (commandLength == 0) {
+        mWriter.reset();
+        return Error::NONE;
+    }
+
     Error error = kDefaultError;
     auto ret = mClient->executeCommands(commandLength, commandHandles,
             [&](const auto& tmpError, const auto& tmpOutChanged,
diff --git a/services/surfaceflinger/DisplayHardware/ComposerHal.h b/services/surfaceflinger/DisplayHardware/ComposerHal.h
index 31a3c1d..104ca60 100644
--- a/services/surfaceflinger/DisplayHardware/ComposerHal.h
+++ b/services/surfaceflinger/DisplayHardware/ComposerHal.h
@@ -152,6 +152,9 @@
     // skip a frame but have already queued some commands.
     void resetCommands();
 
+    // Explicitly flush all pending commands in the command buffer.
+    Error executeCommands();
+
     uint32_t getMaxVirtualDisplayCount();
     bool isUsingVrComposer() const { return mIsUsingVrComposer; }
     Error createVirtualDisplay(uint32_t width, uint32_t height,
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index 78c0c85..ab4a4b2 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -221,6 +221,11 @@
     }
 }
 
+Error Device::flushCommands()
+{
+    return static_cast<Error>(mComposer->executeCommands());
+}
+
 // Display methods
 
 Display::Display(android::Hwc2::Composer& composer,
@@ -632,11 +637,6 @@
     return error;
 }
 
-void Display::discardCommands()
-{
-    mComposer.resetCommands();
-}
-
 // For use by Device
 
 void Display::setConnected(bool connected) {
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.h b/services/surfaceflinger/DisplayHardware/HWC2.h
index fbe4c7e..a15c6d9 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.h
+++ b/services/surfaceflinger/DisplayHardware/HWC2.h
@@ -106,6 +106,11 @@
 
     android::Hwc2::Composer* getComposer() { return mComposer.get(); }
 
+    // We buffer most state changes and flush them implicitly with
+    // Display::validate, Display::present, and Display::presentOrValidate.
+    // This method provides an explicit way to flush state changes to HWC.
+    Error flushCommands();
+
 private:
     // Initialization methods
 
@@ -244,12 +249,6 @@
                                                  uint32_t* outNumRequests,
                                                           android::sp<android::Fence>* outPresentFence, uint32_t* state);
 
-    // Most methods in this class write a command to a command buffer.  The
-    // command buffer is implicitly submitted in validate, present, and
-    // presentOrValidate.  This method provides a way to discard the commands,
-    // which can be used to discard stale commands.
-    void discardCommands();
-
     // Other Display methods
 
     hwc2_display_t getId() const { return mId; }
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index b096a3a..5328a22 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -605,8 +605,11 @@
     auto& hwcDisplay = displayData.hwcDisplay;
 
     if (displayData.validateWasSkipped) {
-        hwcDisplay->discardCommands();
-        auto error = displayData.presentError;
+        // explicitly flush all pending commands
+        auto error = mHwcDevice->flushCommands();
+        if (displayData.presentError != HWC2::Error::None) {
+            error = displayData.presentError;
+        }
         if (error != HWC2::Error::None) {
             ALOGE("skipValidate: failed for display %d: %s (%d)",
                   displayId, to_string(error).c_str(), static_cast<int32_t>(error));