commit 027d365531303be8bd0da2f2ee3f816459258752
author Dan Stoza <stoza@google.com> Tue May 26 17:26:34 2020 -0700
committer Dan Stoza <stoza@google.com> Mon Jun 01 13:54:50 2020 -0700
tree f137b51f53c7984b96160a8b1eb07d7a2153e7e8
parent 9b5bf0f42d57387a3451aa9eb9bfb1075fcb91a4

SF: Reconfirm all period changes, ignore HWC

This change includes two separate fixes to make waking up from idle more
robust when using a kernel idle timer:

  1) Always reconfirm the refresh rate when we resync to hardware vsync.
     This is because if the kernel idle timer is enabled, we may not
     immediately be in the refresh rate we expect to be.
  2) Ignore the refresh rate reported by the hardware vsync callbacks,
     since that refresh rate may not reflect the actual refresh rate
     when the kernel idle timer is in effect.

Bug: 154303580
Test: systrace
Test: libsurfaceflinger_unittest
Change-Id: I79c66faeaed262acd9c5925fe2202a9fb3f10b7b

services/surfaceflinger/Scheduler/VSyncReactor.cpp

diff --git a/services/surfaceflinger/Scheduler/VSyncReactor.cpp b/services/surfaceflinger/Scheduler/VSyncReactor.cpp
index 5f0c9ce..16d102c 100644
--- a/services/surfaceflinger/Scheduler/VSyncReactor.cpp
+++ b/services/surfaceflinger/Scheduler/VSyncReactor.cpp
@@ -56,14 +56,16 @@
 };
 
 VSyncReactor::VSyncReactor(std::unique_ptr<Clock> clock, std::unique_ptr<VSyncDispatch> dispatch,
-                           std::unique_ptr<VSyncTracker> tracker, size_t pendingFenceLimit)
+                           std::unique_ptr<VSyncTracker> tracker, size_t pendingFenceLimit,
+                           bool supportKernelIdleTimer)
       : mClock(std::move(clock)),
         mTracker(std::move(tracker)),
         mDispatch(std::move(dispatch)),
         mPendingLimit(pendingFenceLimit),
         mPredictedVsyncTracer(property_get_bool("debug.sf.show_predicted_vsync", false)
                                       ? std::make_unique<PredictedVsyncTracer>(*mDispatch)
-                                      : nullptr) {}
+                                      : nullptr),
+        mSupportKernelIdleTimer(supportKernelIdleTimer) {}
 
 VSyncReactor::~VSyncReactor() = default;
 
@@ -249,7 +251,8 @@
     ATRACE_INT64("VSR-setPeriod", period);
     std::lock_guard lk(mMutex);
     mLastHwVsync.reset();
-    if (period == getPeriod()) {
+
+    if (!mSupportKernelIdleTimer && period == getPeriod()) {
         endPeriodTransition();
     } else {
         startPeriodTransition(period);
@@ -275,6 +278,11 @@
         return false;
     }
 
+    if (mSupportKernelIdleTimer) {
+        // Clear out the Composer-provided period and use the allowance logic below
+        HwcVsyncPeriod = {};
+    }
+
     auto const period = mPeriodTransitioningTo ? *mPeriodTransitioningTo : getPeriod();
     static constexpr int allowancePercent = 10;
     static constexpr std::ratio<allowancePercent, 100> allowancePercentRatio;