[AChoreographer] Add refresh rate callback.

This will augment the NDK to respond to display events where the display
refresh rate changes. Consumers of this api will include:
* HWUI, for implementing a policy for determining whether to use
render-ahead,
* Swappy, to potentially replace jumping into Java from native code to
respond to display evnets there.
* Any other native app that would rely on the up-to-date display refresh
rate.

Currently however this is not yet exposed to NDK as CTS is not yet
written. Once CTS is written then this will be formally exposed to NDK.
For now we'll leave these as APEX apis to represent incremental
progress.

Bug: 136262896
Test: builds
Change-Id: I66d393f93eb5d681547411e330ef1b8950a35c5d

1 files changed, 22 insertions, 3 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index fed2395fc6..6e827ac4bb 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -956,8 +956,11 @@ void SurfaceFlinger::setActiveConfigInternal() {
     ATRACE_INT("ActiveConfigFPS", refreshRate.fps);
 
     if (mUpcomingActiveConfig.event != Scheduler::ConfigEvent::None) {
+        const nsecs_t vsyncPeriod =
+                mRefreshRateConfigs->getRefreshRateFromConfigId(mUpcomingActiveConfig.configId)
+                        .vsyncPeriod;
         mScheduler->onConfigChanged(mAppConnectionHandle, display->getId()->value,
-                                    mUpcomingActiveConfig.configId);
+                                    mUpcomingActiveConfig.configId, vsyncPeriod);
     }
 }
 
@@ -2614,6 +2617,17 @@ void SurfaceFlinger::initScheduler(DisplayId primaryDisplayId) {
     mRegionSamplingThread =
             new RegionSamplingThread(*this, *mScheduler,
                                      RegionSamplingThread::EnvironmentTimingTunables());
+    // Dispatch a config change request for the primary display on scheduler
+    // initialization, so that the EventThreads always contain a reference to a
+    // prior configuration.
+    //
+    // This is a bit hacky, but this avoids a back-pointer into the main SF
+    // classes from EventThread, and there should be no run-time binder cost
+    // anyway since there are no connected apps at this point.
+    const nsecs_t vsyncPeriod =
+            mRefreshRateConfigs->getRefreshRateFromConfigId(currentConfig).vsyncPeriod;
+    mScheduler->onConfigChanged(mAppConnectionHandle, primaryDisplayId.value, currentConfig,
+                                vsyncPeriod);
 }
 
 void SurfaceFlinger::commitTransaction()
@@ -5499,7 +5513,10 @@ status_t SurfaceFlinger::setDesiredDisplayConfigSpecsInternal(const sp<DisplayDe
 
         auto configId = HwcConfigIndexType(defaultConfig);
         display->setActiveConfig(configId);
-        mScheduler->onConfigChanged(mAppConnectionHandle, display->getId()->value, configId);
+        const nsecs_t vsyncPeriod =
+                mRefreshRateConfigs->getRefreshRateFromConfigId(configId).vsyncPeriod;
+        mScheduler->onConfigChanged(mAppConnectionHandle, display->getId()->value, configId,
+                                    vsyncPeriod);
         return NO_ERROR;
     }
 
@@ -5523,8 +5540,10 @@ status_t SurfaceFlinger::setDesiredDisplayConfigSpecsInternal(const sp<DisplayDe
     // TODO(b/140204874): This hack triggers a notification that something has changed, so
     // that listeners that care about a change in allowed configs can get the notification.
     // Giving current ActiveConfig so that most other listeners would just drop the event
+    const nsecs_t vsyncPeriod =
+            mRefreshRateConfigs->getRefreshRateFromConfigId(display->getActiveConfig()).vsyncPeriod;
     mScheduler->onConfigChanged(mAppConnectionHandle, display->getId()->value,
-                                display->getActiveConfig());
+                                display->getActiveConfig(), vsyncPeriod);
 
     if (mRefreshRateConfigs->refreshRateSwitchingSupported()) {
         auto configId = mScheduler->getPreferredConfigId();