surfaceflinger: add getDisplayStats() method

This is used by media service to schedule video frames at the
proper time, based on precise vsync timings.

Bug: 14659809
Change-Id: I1a90603f3dc09dca9aa4f90a3aa845fab56e0a5e

1 files changed, 6 insertions, 0 deletions

diff --git a/services/surfaceflinger/DispSync.cpp b/services/surfaceflinger/DispSync.cpp
index 12da9a5..3738a55 100644
--- a/services/surfaceflinger/DispSync.cpp
+++ b/services/surfaceflinger/DispSync.cpp
@@ -408,6 +408,12 @@ void DispSync::setPeriod(nsecs_t period) {
     mThread->updateModel(mPeriod, mPhase);
 }
 
+nsecs_t DispSync::getPeriod() {
+    // lock mutex as mPeriod changes multiple times in updateModelLocked
+    Mutex::Autolock lock(mMutex);
+    return mPeriod;
+}
+
 void DispSync::updateModelLocked() {
     if (mNumResyncSamples >= MIN_RESYNC_SAMPLES_FOR_UPDATE) {
         nsecs_t durationSum = 0;