From c159da765bfeed47ca45ac0645d98de303b56def Mon Sep 17 00:00:00 2001 From: "Wang, Yue A" Date: Tue, 21 Jan 2014 17:42:13 +0800 Subject: [PATCH] SurfaceFlinger: disable VSync thread if no clients requiring. In EventThread, 2 VSYNCs are needed to do composition and update the client status. So, a 30FPS video may leads to 60FPS VSYNC, which means the DispSync thread would be waked 60FPS. This is a unexpected behavior which takes more power consumption. Now we update the SF status soon after the first VSYNC, which means no extra VSYNC needed, and the DispSync could be awaked as expected, and consequently power get saved. Change-Id: If486eb9b87f109a71f71b510768f15dd733f1233 Orig-Change-Id: I1d3b166021e15a81b2ad770b039761fc2c15fddf Tracked-On: https://jira01.devtools.intel.com/browse/IMINAN-12211 Category: aosp improvement Domain: Graphics-SF Origin: internal Upstream-Candidate: yes Signed-off-by: Wang, Yue A Reviewed-on: https://android.intel.com:443/238344 --- services/surfaceflinger/EventThread.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/services/surfaceflinger/EventThread.cpp b/services/surfaceflinger/EventThread.cpp index 973a8bc4c..c8cf4bf5f 100644 --- a/services/surfaceflinger/EventThread.cpp +++ b/services/surfaceflinger/EventThread.cpp @@ -283,11 +283,11 @@ Vector< sp > EventThread::waitForEvent( } // Here we figure out if we need to enable or disable vsyncs - if (timestamp && !waitForVSync) { - // we received a VSYNC but we have no clients - // don't report it, and disable VSYNC events + if (!waitForVSync) { + // we have no clients waiting on next VSYNC + // just disable VSYNC events. disableVSyncLocked(); - } else if (!timestamp && waitForVSync) { + } else if (!timestamp) { // we have at least one client, so we want vsync enabled // (TODO: this function is called right after we finish // notifying clients of a vsync, so this call will be made