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Commit d94d3b89 authored by Mathias Agopian's avatar Mathias Agopian
Browse files

avoid turning vsync off/on at each frame 

always keep vsync active for an extra frame before
deciding if it should be turned off.

Change-Id: I55b03265b7851b33a595e46a013f2ab55e66c964
parent c522a6a5

services/surfaceflinger/EventThread.cpp

+24 −10
Original line number Diff line number Diff line
@@ -123,13 +123,9 @@ bool EventThread::threadLoop() { 


        Mutex::Autolock _l(mLock);

        do {

            // check if we have received a VSYNC event

            if (mVSyncTimestamp) {

                // we have a VSYNC event pending

            // latch VSYNC event if any

            timestamp = mVSyncTimestamp;

            mVSyncTimestamp = 0;

                break;

            }



            // check if we should be waiting for VSYNC events

            bool waitForNextVsync = false;
@@ -144,9 +140,27 @@ bool EventThread::threadLoop() { 
                }

            }



            // enable or disable VSYNC events

            if (timestamp) {

                if (!waitForNextVsync) {

                    // we received a VSYNC but we have no clients

                    // don't report it, and disable VSYNC events

                    mHw.getHwComposer().eventControl(

                    HWComposer::EVENT_VSYNC, waitForNextVsync);

                            HWComposer::EVENT_VSYNC, false);

                } else {

                    // report VSYNC event

                    break;

                }

            } else {

                // never disable VSYNC events immediately, instead

                // we'll wait to receive the event and we'll

                // reevaluate whether we need to dispatch it and/or

                // disable VSYNC events then.

                if (waitForNextVsync) {

                    // enable

                    mHw.getHwComposer().eventControl(

                            HWComposer::EVENT_VSYNC, true);

                }

            }



            // wait for something to happen

            mCondition.wait(mLock);