I've observed that "FIFO is overflown by GatherPipe" is not real overflow.

Really that happens because the fifo.CPReadWriteDistance is negative.
Example: CPReadWriteDistance: -864 CPEnd: 10092672 fifo.CPBase: 9568416
In SMG this is because  PI_FIFO_RESET is writing and after fifo.CPReadWriteDistance will be setted to 0.
To Prevent that, I've Implemented AbortFrame function in the CommmandProcessor. It should fix overflown because of that. 
Note: There is other issue (Issue 2846) where the fifo.CPReadWriteDistance is negative too but the effect is different.
I'm working to solve this.


git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@6083 8ced0084-cf51-0410-be5f-012b33b47a6e

Source/Core/Common/Src/PluginVideo.cpp

@@ -39,6 +39,7 @@ PluginVideo::PluginVideo(const char *_Filename) : CPlugin(_Filename), validVideo
     Video_GatherPipeBursted = 0;
     Video_WaitForFrameFinish = 0;
 	Video_IsFifoBusy = 0;
+	Video_AbortFrame = 0;
 
 	Video_Prepare  = reinterpret_cast<TVideo_Prepare>
 		(LoadSymbol("Video_Prepare"));
@@ -74,6 +75,8 @@ PluginVideo::PluginVideo(const char *_Filename) : CPlugin(_Filename), validVideo
 		(LoadSymbol("Video_WaitForFrameFinish"));
     Video_IsFifoBusy = reinterpret_cast<TVideo_IsFifoBusy>
 		(LoadSymbol("Video_IsFifoBusy"));
+    Video_AbortFrame = reinterpret_cast<TVideo_AbortFrame>
+		(LoadSymbol("Video_AbortFrame"));	
 	if ((Video_Prepare                  != 0) &&
 		(Video_BeginField               != 0) &&
 		(Video_EndField                 != 0) &&
@@ -91,7 +94,8 @@ PluginVideo::PluginVideo(const char *_Filename) : CPlugin(_Filename), validVideo
         (Video_PixelEngineWrite32       != 0) &&
         (Video_GatherPipeBursted        != 0) &&
         (Video_WaitForFrameFinish       != 0) &&
-		(Video_IsFifoBusy		        != 0))
+		(Video_IsFifoBusy		        != 0) &&
+		(Video_AbortFrame               != 0))
 		validVideo = true;
 }
 

Source/Core/Common/Src/PluginVideo.h

@@ -40,6 +40,7 @@ typedef void (__cdecl* TVideo_Write32)(const u32 _Data, const u32 _Address);
 typedef void (__cdecl* TVideo_GatherPipeBursted)();
 typedef void (__cdecl* TVideo_WaitForFrameFinish)();
 typedef bool (__cdecl* TVideo_IsFifoBusy)();
+typedef void (__cdecl* TVideo_AbortFrame)();
 
 class PluginVideo : public CPlugin
 {
@@ -68,6 +69,7 @@ public:
     TVideo_GatherPipeBursted    Video_GatherPipeBursted;
     TVideo_WaitForFrameFinish   Video_WaitForFrameFinish;
 	TVideo_IsFifoBusy		    Video_IsFifoBusy;
+	TVideo_AbortFrame		    Video_AbortFrame;
 private:
 	bool validVideo;
 };

Source/Core/Core/Src/HW/ProcessorInterface.cpp

@@ -24,7 +24,7 @@
 #include "../CoreTiming.h"
 #include "ProcessorInterface.h"
 #include "GPFifo.h"
-
+#include "../PluginManager.h"
 namespace ProcessorInterface
 {
 
@@ -181,6 +181,8 @@ void Write32(const u32 _uValue, const u32 _iAddress)
 		break;
 
     case PI_FIFO_RESET:
+		//Abort the actual frame
+		CPluginManager::GetInstance().GetVideo()->Video_AbortFrame();
         //Fifo_CPUWritePointer = Fifo_CPUBase; ??
 		//PanicAlert("Unknown write to PI_FIFO_RESET (%08x)", _uValue);
 		WARN_LOG(PROCESSORINTERFACE, "Fifo reset (%08x)", _uValue);

Source/Core/VideoCommon/Src/CommandProcessor.cpp

@@ -701,4 +701,18 @@ void SetFifoIdleFromVideoPlugin()
 	s_fifoIdleEvent.Set();
 }
 
+// This is called by the ProcessorInterface when PI_FIFO_RESET is writed,
+// the general idea is abort all commands in the FIFO. 
+// This prevent Negative fifo.CPReadWriteDistance because when PI_FIFO_RESET happens
+// the fifo.CPReadWriteDistance is writed to 0
+void AbortFrame()
+{
+	Fifo_SetRendering(false);
+		while(!fifo.CPCmdIdle)
+			Common::YieldCPU();
+	Fifo_SetRendering(true);
+	PixelEngine::ResetSetToken();
+	PixelEngine::ResetSetFinish();
+}
+
 } // end of namespace CommandProcessor

Source/Core/VideoCommon/Src/CommandProcessor.h

@@ -162,6 +162,7 @@ void WaitForFrameFinish();
 void FifoCriticalEnter();
 void FifoCriticalLeave();
 
+void AbortFrame();
 } // namespace CommandProcessor
 
 #endif // _COMMANDPROCESSOR_H

Source/Core/VideoCommon/Src/PixelEngine.cpp

@@ -393,4 +393,16 @@ void ResetSetFinish()
 	}
 }
 
+void ResetSetToken()
+{
+	if (g_bSignalTokenInterrupt)
+	{
+		g_VideoInitialize.pSetInterrupt(INT_CAUSE_PE_TOKEN, false);
+		g_bSignalTokenInterrupt = false;
+		
+	}else
+	{
+		g_VideoInitialize.pRemoveEvent(et_SetTokenOnMainThread);
+	}
+}
 } // end of namespace PixelEngine

Source/Core/VideoCommon/Src/PixelEngine.h

@@ -68,6 +68,7 @@ void Write32(const u32 _iValue, const u32 _iAddress);
 void SetToken(const u16 _token, const int _bSetTokenAcknowledge);
 void SetFinish(void);
 void ResetSetFinish(void);
+void ResetSetToken(void);
 bool AllowIdleSkipping();
 
 // Bounding box functionality. Paper Mario (both) are a couple of the few games that use it.

Source/PluginSpecs/pluginspecs_video.h

@@ -189,5 +189,7 @@ EXPORT void CALL Video_WaitForFrameFinish(void);
 //
 EXPORT bool CALL Video_IsFifoBusy(void);
 
+EXPORT void CALL Video_AbortFrame(void);
+
 #include "ExportEpilog.h"
 #endif

Source/Plugins/Plugin_VideoDX11/Src/main.cpp

@@ -453,3 +453,8 @@ bool Video_IsFifoBusy(void)
 {
 	return CommandProcessor::isFifoBusy;
 }
+
+void Video_AbortFrame(void)
+{
+	CommandProcessor::AbortFrame();
+}

Source/Plugins/Plugin_VideoDX9/Src/main.cpp

@@ -479,3 +479,8 @@ bool Video_IsFifoBusy(void)
 {
 	return CommandProcessor::isFifoBusy;
 }
+
+void Video_AbortFrame(void)
+{
+	CommandProcessor::AbortFrame();
+}

Source/Plugins/Plugin_VideoOGL/Src/main.cpp

@@ -510,3 +510,8 @@ bool Video_IsFifoBusy(void)
 {
 	return CommandProcessor::isFifoBusy;
 }
+
+void Video_AbortFrame(void)
+{
+	CommandProcessor::AbortFrame();
+}

Source/Plugins/Plugin_VideoSoftware/Src/main.cpp

@@ -220,3 +220,7 @@ bool Video_IsFifoBusy(void)
 {
 	return false;
 }
+
+void Video_AbortFrame(void)
+{
+}