commit 0f4a1b19009a1e71ed2100b63b04aa015a111b44
author Ady Abraham <adyabr@google.com> Tue Jun 04 16:04:04 2019 -0700
committer Ady Abraham <adyabr@google.com> Wed Jun 05 13:43:12 2019 -0700
tree ae569ff5a05c053c3726d3cea1bb57367f1f7c76
parent 2eeb9c63869b295e444604d7c5470ce6be3744a0

SurfaceFlinger: add explicit register for DISPLAY_EVENT_CONFIG_CHANGED

When display refresh rate changes, SF fires DISPLAY_EVENT_CONFIG_CHANGED
thru DisplayEventReceiver. If the other end of the pipe doesn't consume
the events it may lead to pipe full and dropping of events. Furthermore,
The only clients interested in this event in DisplayManager and hwui.

To avoid spamming all clients with this event, this change is adding an
explicit register for DISPLAY_EVENT_CONFIG_CHANGED events.

Bug: 131688378
Test: adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest
Test: trigger config change and observe logcat
Change-Id: I5973a1ecc1f3e3ff8d8a0cba19db0e49ef0d5341

services/surfaceflinger/Scheduler/EventThread.cpp

diff --git a/services/surfaceflinger/Scheduler/EventThread.cpp b/services/surfaceflinger/Scheduler/EventThread.cpp
index 05bad4d..9d1f777 100644
--- a/services/surfaceflinger/Scheduler/EventThread.cpp
+++ b/services/surfaceflinger/Scheduler/EventThread.cpp
@@ -76,6 +76,10 @@
             return StringPrintf("VSync{displayId=%" ANDROID_PHYSICAL_DISPLAY_ID_FORMAT
                                 ", count=%u}",
                                 event.header.displayId, event.vsync.count);
+        case DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED:
+            return StringPrintf("ConfigChanged{displayId=%" ANDROID_PHYSICAL_DISPLAY_ID_FORMAT
+                                ", configId=%u}",
+                                event.header.displayId, event.config.configId);
         default:
             return "Event{}";
     }
@@ -107,8 +111,10 @@
 } // namespace
 
 EventThreadConnection::EventThreadConnection(EventThread* eventThread,
-                                             ResyncCallback resyncCallback)
+                                             ResyncCallback resyncCallback,
+                                             ISurfaceComposer::ConfigChanged configChanged)
       : resyncCallback(std::move(resyncCallback)),
+        configChanged(configChanged),
         mEventThread(eventThread),
         mChannel(gui::BitTube::DefaultSize) {}
 
@@ -203,8 +209,10 @@
     mVSyncSource->setPhaseOffset(phaseOffset);
 }
 
-sp<EventThreadConnection> EventThread::createEventConnection(ResyncCallback resyncCallback) const {
-    return new EventThreadConnection(const_cast<EventThread*>(this), std::move(resyncCallback));
+sp<EventThreadConnection> EventThread::createEventConnection(
+        ResyncCallback resyncCallback, ISurfaceComposer::ConfigChanged configChanged) const {
+    return new EventThreadConnection(const_cast<EventThread*>(this), std::move(resyncCallback),
+                                     configChanged);
 }
 
 status_t EventThread::registerDisplayEventConnection(const sp<EventThreadConnection>& connection) {
@@ -398,9 +406,11 @@
                                      const sp<EventThreadConnection>& connection) const {
     switch (event.header.type) {
         case DisplayEventReceiver::DISPLAY_EVENT_HOTPLUG:
-        case DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED:
             return true;
 
+        case DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED:
+            return connection->configChanged == ISurfaceComposer::eConfigChangedDispatch;
+
         case DisplayEventReceiver::DISPLAY_EVENT_VSYNC:
             switch (connection->vsyncRequest) {
                 case VSyncRequest::None: