From 6200eacdc927776483d775562db11cce284cc7e0 Mon Sep 17 00:00:00 2001
From: Chia-I Wu <olv@google.com>
Date: Thu, 5 Oct 2017 14:24:41 -0700
Subject: surfaceflinger: make vsync injection more robust

There are more issues than I expected :)

 - no lock to synchronize enable/disable and injection
 - Every time injection is diabled and enabled, a new EventThread is
   created
 - mCallback might be nullptr
 - ENABLE_VSYNC_INJECTIONS/INJECT_VSYNC should require special
   permission
 - MessageQueue::setEventThread must be called from the main thread
 - MessageQueue::setEventThread does not handle EventThread switch
   well

Bug: 65483324
Test: manual
Merged-In: I7d7b98d1f57afc64af0f2065a9bc7c8ad004ca9f
Change-Id: I7d7b98d1f57afc64af0f2065a9bc7c8ad004ca9f
---
 services/surfaceflinger/MessageQueue.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'services/surfaceflinger/MessageQueue.cpp')

diff --git a/services/surfaceflinger/MessageQueue.cpp b/services/surfaceflinger/MessageQueue.cpp
index bca3430794..0b1199c2d0 100644
--- a/services/surfaceflinger/MessageQueue.cpp
+++ b/services/surfaceflinger/MessageQueue.cpp
@@ -91,6 +91,14 @@ void MessageQueue::init(const sp<SurfaceFlinger>& flinger)
 
 void MessageQueue::setEventThread(const sp<EventThread>& eventThread)
 {
+    if (mEventThread == eventThread) {
+        return;
+    }
+
+    if (mEventTube.getFd() >= 0) {
+        mLooper->removeFd(mEventTube.getFd());
+    }
+
     mEventThread = eventThread;
     mEvents = eventThread->createEventConnection();
     mEvents->stealReceiveChannel(&mEventTube);
-- 
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