SurfaceFlinger: Add EventControlThread
This change adds a new thread for calling HWComposer's eventControl
asynchronously. The DispSync-based vsync approach ends up enabling and
disabling HWComposer's vsync callbacks at arbitrary times, and some HWComposer
implementations do not have these calls optimized.
Bug: 11175503
Change-Id: I719be82bd200b391c61d40863b991c7b59acdfd6
diff --git a/services/surfaceflinger/EventControlThread.cpp b/services/surfaceflinger/EventControlThread.cpp
new file mode 100644
index 0000000..6504091
--- /dev/null
+++ b/services/surfaceflinger/EventControlThread.cpp
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#include "EventControlThread.h"
+#include "SurfaceFlinger.h"
+
+namespace android {
+
+EventControlThread::EventControlThread(const sp<SurfaceFlinger>& flinger):
+ mFlinger(flinger),
+ mVsyncEnabled(false) {
+}
+
+void EventControlThread::setVsyncEnabled(bool enabled) {
+ Mutex::Autolock lock(mMutex);
+ mVsyncEnabled = enabled;
+ mCond.signal();
+}
+
+bool EventControlThread::threadLoop() {
+ Mutex::Autolock lock(mMutex);
+
+ bool vsyncEnabled = mVsyncEnabled;
+
+ mFlinger->eventControl(HWC_DISPLAY_PRIMARY, SurfaceFlinger::EVENT_VSYNC,
+ mVsyncEnabled);
+
+ while (true) {
+ status_t err = mCond.wait(mMutex);
+ if (err != NO_ERROR) {
+ ALOGE("error waiting for new events: %s (%d)",
+ strerror(-err), err);
+ return false;
+ }
+
+ if (vsyncEnabled != mVsyncEnabled) {
+ mFlinger->eventControl(HWC_DISPLAY_PRIMARY,
+ SurfaceFlinger::EVENT_VSYNC, mVsyncEnabled);
+ vsyncEnabled = mVsyncEnabled;
+ }
+ }
+
+ return false;
+}
+
+} // namespace android