From ed8f293b4f4c340dc342e54532fcdd953056efab Mon Sep 17 00:00:00 2001
From: Shawn Hoffman <godisgovernment@gmail.com>
Date: Thu, 22 Jun 2017 05:42:14 -0700
Subject: [PATCH] Change "blocking" BlockingLoop::Stop to give up and die after
 a timeout. This fixes the global-static fifo object causing infinite hangs in
 some cases. Notably, failure to initialize a graphics backend would result in
 BlockingLoop::Prepare being called but never executing Run(), leaving the
 object in a bad state.

---
 Source/Core/Common/BlockingLoop.h | 23 ++++++++++++++++++++---
 Source/Core/VideoCommon/Fifo.cpp  |  2 +-
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/Source/Core/Common/BlockingLoop.h b/Source/Core/Common/BlockingLoop.h
index a1ebe7d708..f8e9f85164 100644
--- a/Source/Core/Common/BlockingLoop.h
+++ b/Source/Core/Common/BlockingLoop.h
@@ -22,8 +22,15 @@ namespace Common
 class BlockingLoop
 {
 public:
+  enum StopMode
+  {
+    kNonBlock,
+    kBlock,
+    kBlockAndGiveUp,
+  };
+
   BlockingLoop() { m_stopped.Set(); }
-  ~BlockingLoop() { Stop(); }
+  ~BlockingLoop() { Stop(kBlockAndGiveUp); }
   // Triggers to rerun the payload of the Run() function at least once again.
   // This function will never block and is designed to finish as fast as possible.
   void Wakeup()
@@ -192,7 +199,7 @@ public:
   // Quits the main loop.
   // By default, it will wait until the main loop quits.
   // Be careful to not use the blocking way within the payload of the Run() method.
-  void Stop(bool block = true)
+  void Stop(StopMode mode = kBlock)
   {
     if (m_stopped.IsSet())
       return;
@@ -202,8 +209,18 @@ public:
     // We have to interrupt the sleeping call to let the worker shut down soon.
     Wakeup();
 
-    if (block)
+    switch (mode)
+    {
+    case kBlock:
       Wait();
+      break;
+    case kBlockAndGiveUp:
+      WaitYield(std::chrono::milliseconds(100), [&] {
+        // If timed out, assume no one will come along to call Run, so force a break
+        m_stopped.Set();
+      });
+      break;
+    }
   }
 
   bool IsRunning() const { return !m_stopped.IsSet() && !m_shutdown.IsSet(); }
diff --git a/Source/Core/VideoCommon/Fifo.cpp b/Source/Core/VideoCommon/Fifo.cpp
index cedbea5432..15a1853ee7 100644
--- a/Source/Core/VideoCommon/Fifo.cpp
+++ b/Source/Core/VideoCommon/Fifo.cpp
@@ -144,7 +144,7 @@ void ExitGpuLoop()
 
   // Terminate GPU thread loop
   s_emu_running_state.Set();
-  s_gpu_mainloop.Stop(false);
+  s_gpu_mainloop.Stop(s_gpu_mainloop.kNonBlock);
 }
 
 void EmulatorState(bool running)