From 1da866d7de03e85fac11c55d2e40ed26b570eb76 Mon Sep 17 00:00:00 2001
From: JosJuice <josjuice@gmail.com>
Date: Tue, 5 Jul 2016 18:20:24 +0200
Subject: [PATCH] DVDInterface: Simplify calling ChangeDisc from CPU thread

When Movie was calling ChangeDisc, it was moving execution to
the host thread just to then make the host thread the CPU thread.
We can simply run the code directly on the CPU thread instead.
---
 Source/Core/Core/HW/DVDInterface.cpp   | 15 ++++++++++++---
 Source/Core/Core/HW/DVDInterface.h     |  3 ++-
 Source/Core/Core/Movie.cpp             | 11 ++---------
 Source/Core/DolphinWX/Frame.cpp        |  2 +-
 Source/Core/DolphinWX/FrameTools.cpp   |  2 +-
 Source/Core/DolphinWX/GameListCtrl.cpp |  2 +-
 6 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/Source/Core/Core/HW/DVDInterface.cpp b/Source/Core/Core/HW/DVDInterface.cpp
index ba5a730c1b..ac6b22c0d8 100644
--- a/Source/Core/Core/HW/DVDInterface.cpp
+++ b/Source/Core/Core/HW/DVDInterface.cpp
@@ -472,10 +472,20 @@ static void InsertDiscCallback(u64 userdata, s64 cyclesLate)
   delete _FileName;
 }
 
-void ChangeDisc(const std::string& newFileName)
+// Can only be called by the host thread
+void ChangeDiscAsHost(const std::string& newFileName)
 {
-  // WARNING: Can only run on Host Thread
   bool was_unpaused = Core::PauseAndLock(true);
+
+  // The host thread is now temporarily the CPU thread
+  ChangeDiscAsCPU(newFileName);
+
+  Core::PauseAndLock(false, was_unpaused);
+}
+
+// Can only be called by the CPU thread
+void ChangeDiscAsCPU(const std::string& newFileName)
+{
   std::string* _FileName = new std::string(newFileName);
   CoreTiming::ScheduleEvent(0, s_eject_disc);
   CoreTiming::ScheduleEvent(500000000, s_insert_disc, (u64)_FileName);
@@ -492,7 +502,6 @@ void ChangeDisc(const std::string& newFileName)
     }
     Movie::g_discChange = fileName.substr(sizeofpath);
   }
-  Core::PauseAndLock(false, was_unpaused);
 }
 
 void SetLidOpen(bool open)
diff --git a/Source/Core/Core/HW/DVDInterface.h b/Source/Core/Core/HW/DVDInterface.h
index a67fd39baf..640afe1d84 100644
--- a/Source/Core/Core/HW/DVDInterface.h
+++ b/Source/Core/Core/HW/DVDInterface.h
@@ -108,7 +108,8 @@ bool VolumeIsValid();
 // Disc detection and swapping
 void SetDiscInside(bool _DiscInside);
 bool IsDiscInside();
-void ChangeDisc(const std::string& fileName);  // [NOT THREADSAFE] Host only
+void ChangeDiscAsHost(const std::string& path);  // Can only be called by the host thread
+void ChangeDiscAsCPU(const std::string& path);   // Can only be called by the CPU thread
 
 // DVD Access Functions
 bool ChangePartition(u64 offset);
diff --git a/Source/Core/Core/Movie.cpp b/Source/Core/Core/Movie.cpp
index 3ebed8b7ef..d8f085bcb8 100644
--- a/Source/Core/Core/Movie.cpp
+++ b/Source/Core/Core/Movie.cpp
@@ -1215,7 +1215,6 @@ void PlayController(GCPadStatus* PadStatus, int controllerID)
     // that will cause
     // it to load the last disc every time. As far as i know though, there are no 3+ disc games, so
     // this should be fine.
-    CPU::Break();
     bool found = false;
     std::string path;
     for (size_t i = 0; i < SConfig::GetInstance().m_ISOFolder.size(); ++i)
@@ -1230,17 +1229,11 @@ void PlayController(GCPadStatus* PadStatus, int controllerID)
     if (found)
     {
       path += '/' + g_discChange;
-
-      Core::QueueHostJob([=] {
-        if (!Movie::IsPlayingInput())
-          return;
-
-        DVDInterface::ChangeDisc(path);
-        CPU::EnableStepping(false);
-      });
+      DVDInterface::ChangeDiscAsCPU(path);
     }
     else
     {
+      CPU::Break();
       PanicAlertT("Change the disc to %s", g_discChange.c_str());
     }
   }
diff --git a/Source/Core/DolphinWX/Frame.cpp b/Source/Core/DolphinWX/Frame.cpp
index b853384b22..de6c5cc141 100644
--- a/Source/Core/DolphinWX/Frame.cpp
+++ b/Source/Core/DolphinWX/Frame.cpp
@@ -124,7 +124,7 @@ void CRenderFrame::OnDropFiles(wxDropFilesEvent& event)
   }
   else
   {
-    DVDInterface::ChangeDisc(filepath);
+    DVDInterface::ChangeDiscAsHost(filepath);
   }
 }
 
diff --git a/Source/Core/DolphinWX/FrameTools.cpp b/Source/Core/DolphinWX/FrameTools.cpp
index 44de0e8e99..68bd5d6754 100644
--- a/Source/Core/DolphinWX/FrameTools.cpp
+++ b/Source/Core/DolphinWX/FrameTools.cpp
@@ -691,7 +691,7 @@ void CFrame::DoOpen(bool Boot)
   }
   else
   {
-    DVDInterface::ChangeDisc(WxStrToStr(path));
+    DVDInterface::ChangeDiscAsHost(WxStrToStr(path));
   }
 }
 
diff --git a/Source/Core/DolphinWX/GameListCtrl.cpp b/Source/Core/DolphinWX/GameListCtrl.cpp
index db2eede260..f8b0bf061c 100644
--- a/Source/Core/DolphinWX/GameListCtrl.cpp
+++ b/Source/Core/DolphinWX/GameListCtrl.cpp
@@ -1331,7 +1331,7 @@ void CGameListCtrl::OnChangeDisc(wxCommandEvent& WXUNUSED(event))
   const GameListItem* iso = GetSelectedISO();
   if (!iso || !Core::IsRunning())
     return;
-  DVDInterface::ChangeDisc(WxStrToStr(iso->GetFileName()));
+  DVDInterface::ChangeDiscAsHost(WxStrToStr(iso->GetFileName()));
 }
 
 void CGameListCtrl::OnSize(wxSizeEvent& event)