GIF: Implement GIF FIFO - Enabled as hack as it is slow

-Fixes DJ Hero, Wallace & Gromit (properly), Hot Wheels (closer)

pcsx2/Config.h

@@ -55,7 +55,7 @@ enum GamefixId
 	Fix_DMABusy,
 	Fix_VIFFIFO,
 	Fix_VIF1Stall,
-	Fix_GIFReverse,
+	Fix_GIFFIFO,
 	Fix_FMVinSoftware,
 	Fix_GoemonTlbMiss,
 	Fix_ScarfaceIbit,
@@ -343,7 +343,7 @@ struct Pcsx2Config
 				DMABusyHack		:1,		// Denies writes to the DMAC when it's busy. This is correct behaviour but bad timing can cause problems.
 				VIFFIFOHack		:1,     // Pretends to fill the non-existant VIF FIFO Buffer.
 				VIF1StallHack   :1,     // Like above, processes FIFO data before the stall is allowed (to make sure data goes over).
-				GIFReverseHack  :1,		// Allows PATH3 to continue even if the FIFO is reversed.
+				GIFFIFOHack		:1,		// Enabled the GIF FIFO (more correct but slower)
 				FMVinSoftwareHack:1,	// Toggle in and out of software rendering when an FMV runs.
 				GoemonTlbHack	:1,		// Gomeon tlb miss hack. The game need to access unmapped virtual address. Instead to handle it as exception, tlb are preloaded at startup
 				ScarfaceIbit 	:1;		// Scarface I bit hack. Needed to stop constant VU recompilation
@@ -525,7 +525,7 @@ TraceLogFilters&				SetTraceConfig();
 #define CHECK_DMABUSYHACK			(EmuConfig.Gamefixes.DMABusyHack)    // Denies writes to the DMAC when it's busy. This is correct behaviour but bad timing can cause problems.
 #define CHECK_VIFFIFOHACK			(EmuConfig.Gamefixes.VIFFIFOHack)    // Pretends to fill the non-existant VIF FIFO Buffer.
 #define CHECK_VIF1STALLHACK			(EmuConfig.Gamefixes.VIF1StallHack)  // Like above, processes FIFO data before the stall is allowed (to make sure data goes over).
-#define CHECK_GIFREVERSEHACK		(EmuConfig.Gamefixes.GIFReverseHack) // Allows PATH3 to continue even if the FIFO is reversed.
+#define CHECK_GIFFIFOHACK			(EmuConfig.Gamefixes.GIFFIFOHack)	 // Enabled the GIF FIFO (more correct but slower)
 #define CHECK_FMVINSOFTWAREHACK	 	(EmuConfig.Gamefixes.FMVinSoftwareHack) // Toggle in and out of software rendering when an FMV runs.
 //------------ Advanced Options!!! ---------------
 #define CHECK_VU_OVERFLOW			(EmuConfig.Cpu.Recompiler.vuOverflow)

pcsx2/FiFo.cpp

@@ -18,6 +18,7 @@
 #include "Common.h"
 
 #include "GS.h"
+#include "Gif.h"
 #include "Gif_Unit.h"
 #include "Vif.h"
 #include "Vif_Dma.h"
@@ -128,20 +129,28 @@ void __fastcall WriteFIFO_VIF1(const mem128_t *value)
 void __fastcall WriteFIFO_GIF(const mem128_t *value)
 {
 	GUNIT_LOG("WriteFIFO_GIF()");
-	gifUnit.TransferGSPacketData(GIF_TRANS_FIFO, (u8*)value, 16);
+	if (CHECK_GIFFIFOHACK) {
+		gif_fifo.write((u32*)value, 1);
 
-	if(gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_WAIT)
+		gif_fifo.read(true);		
+	}
+	else {
+		gifUnit.TransferGSPacketData(GIF_TRANS_FIFO, (u8*)value, 16);
+	}
+
+	if (gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_WAIT)
 		gifUnit.gifPath[GIF_PATH_3].state = GIF_PATH_IDLE;
 
-	if( gifRegs.stat.APATH == 3 )
+	if (gifRegs.stat.APATH == 3)
 	{
 		gifRegs.stat.APATH = 0;
 		gifRegs.stat.OPH = 0;
 
-		if(gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_IDLE || gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_WAIT) 
+		if (gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_IDLE || gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_WAIT)
 		{
-			if(gifUnit.checkPaths(1,1,0)) gifUnit.Execute(false, true);
+			if (gifUnit.checkPaths(1, 1, 0)) gifUnit.Execute(false, true);
 		}
 
 	}
+	
 }

pcsx2/Gif.cpp

@@ -31,10 +31,86 @@ static u32 gscycles = 0, prevcycles = 0, mfifocycles = 0;
 static u32 gifqwc = 0;
 static bool gifmfifoirq = false;
 
+__aligned16 GIF_Fifo gif_fifo;
+
 static __fi void clearFIFOstuff(bool full) {
 	CSRreg.FIFO = full ? CSR_FIFO_FULL : CSR_FIFO_EMPTY;
 }
 
+void GIF_Fifo::init()
+{
+	readpos = 0;
+	writepos = 0;
+	memzero(data);
+	memzero(readdata);
+	gifRegs.stat.FQC = 0;
+	CSRreg.FIFO = CSR_FIFO_EMPTY;
+}
+
+
+int GIF_Fifo::write(u32* pMem, int size)
+{
+	int transsize;
+	int firsttrans = std::min(size, 16 - (int)gifRegs.stat.FQC);
+
+	gifRegs.stat.FQC += firsttrans;
+	transsize = firsttrans;
+	
+	
+	while (transsize-- > 0)
+	{
+		CopyQWC(&data[writepos], pMem);
+		writepos = (writepos + 4) & 63;
+		pMem += 4;
+	}
+	
+
+	return firsttrans;
+}
+
+int GIF_Fifo::read(bool calledFromDMA)
+{
+	int valueWritePos = 0;
+	uint sizeRead;
+	uint fifoSize = gifRegs.stat.FQC;
+	int oldReadPos = readpos;
+
+	if (!gifUnit.CanDoPath3())
+	{
+		//DevCon.Warning("P3 Masked");
+		return 0;
+	}
+	if (gifRegs.stat.FQC == 0)
+	{
+		//If the GIF isn't stalled and it is waiting to go, fire it off (usually after a path3 mask)
+		if (gifch.chcr.STR == true && !(cpuRegs.interrupt & (1 << DMAC_GIF)) && calledFromDMA == false) {
+			CPU_INT(DMAC_GIF, 16);
+		}
+		return 0;
+	}
+	valueWritePos = 0;
+
+	while (gifRegs.stat.FQC) {
+		CopyQWC(&readdata[valueWritePos], &data[readpos]);
+		readpos = (readpos + 4) & 63;
+		valueWritePos = (valueWritePos + 4) & 63;
+		gifRegs.stat.FQC--;
+	}
+
+	sizeRead = gifUnit.TransferGSPacketData(GIF_TRANS_DMA, (u8*)&readdata[0], fifoSize * 16) / 16; //returns the size actually read
+
+	if (sizeRead < fifoSize) {
+		readpos = (oldReadPos + (sizeRead * 4)) & 63; //if we read less than what was in the fifo, move the read position back
+		gifRegs.stat.FQC = fifoSize - sizeRead;		
+	}
+		
+	if (calledFromDMA == false) {
+		CPU_INT(DMAC_GIF, 16);
+	}	
+	
+	return gifRegs.stat.FQC;
+}
+
 void incGifChAddr(u32 qwc) {
 	if (gifch.chcr.STR) {
 		gifch.madr += qwc * 16;
@@ -44,23 +120,26 @@ void incGifChAddr(u32 qwc) {
 	else DevCon.Error("incGifAddr() Error!");
 }
 
-__fi void gifInterrupt()
+__fi void gifCheckPathStatus() {
-{
+	if (gifRegs.stat.APATH == 3)
-	GIF_LOG("gifInterrupt caught!");
-	if( gifRegs.stat.APATH == 3 )
 	{
 		gifRegs.stat.APATH = 0;
 		gifRegs.stat.OPH = 0;
-		if(gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_IDLE || gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_WAIT) 
+		if (gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_IDLE || gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_WAIT)
 		{
-			if(gifUnit.checkPaths(1,1,0)) gifUnit.Execute(false, true);
+			if (gifUnit.checkPaths(1, 1, 0)) gifUnit.Execute(false, true);
 		}
 
 	}
 
 	//Required for Path3 Masking timing!
-	if(gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_WAIT)
+	if (gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_WAIT)
-			gifUnit.gifPath[GIF_PATH_3].state = GIF_PATH_IDLE;
+		gifUnit.gifPath[GIF_PATH_3].state = GIF_PATH_IDLE;
+}
+__fi void gifInterrupt()
+{
+	GIF_LOG("gifInterrupt caught!");
+	gifCheckPathStatus();
 
 	if(gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_IDLE)
 	{
@@ -85,8 +164,26 @@ __fi void gifInterrupt()
 		return;
 	}	
 
+	if (CHECK_GIFFIFOHACK) {
+
+		if (gif_fifo.read(true)) {
+			CPU_INT(DMAC_GIF, 128);
+		}
+
+		if (!gifUnit.CanDoPath3() && gifRegs.stat.FQC == 16)
+		{
+			if (gifch.qwc > 0 || gspath3done == false) {
+				if (!gifUnit.Path3Masked()) {
+					CPU_INT(DMAC_GIF, 128);
+				}
+				return;
+			}
+		}
+	}
+	
+
 	if (gifUnit.gsSIGNAL.queued) {
-		//DevCon.WriteLn("Path 3 Paused");
+		GIF_LOG("Path 3 Paused");
 		CPU_INT(DMAC_GIF, 128);
 		return;
 	}
@@ -101,16 +198,30 @@ __fi void gifInterrupt()
 			return;
 		}
 		GIFdma();
+		
 		return;
 	}
 
-	gifRegs.stat.FQC = 0;
+	//Double check as we might have read the fifo as it's ending the DMA
+	gifCheckPathStatus();
+
+	if (gifUnit.gifPath[GIF_PATH_3].state == GIF_PATH_IDLE)
+	{
+		if (vif1Regs.stat.VGW)
+		{
+			//Check if VIF is in a cycle or is currently "idle" waiting for GIF to come back.
+			if (!(cpuRegs.interrupt & (1 << DMAC_VIF1))) {
+				CPU_INT(DMAC_VIF1, 1);
+			}
+		}
+	}
+	if (!CHECK_GIFFIFOHACK)gifRegs.stat.FQC = 0;
 	gscycles		 = 0;
 	gspath3done		 = false;
 	gifch.chcr.STR	 = false;
 	clearFIFOstuff(false);
 	hwDmacIrq(DMAC_GIF);
-	DMA_LOG("GIF DMA End");
+	GIF_LOG("GIF DMA End QWC in fifo %x APATH = %x OPH = %x state = %x", gifRegs.stat.FQC, gifRegs.stat.APATH, gifRegs.stat.OPH, gifUnit.gifPath[GIF_PATH_3].state);
 }
 
 static u32 WRITERING_DMA(u32 *pMem, u32 qwc) {
@@ -124,7 +235,13 @@ static u32 WRITERING_DMA(u32 *pMem, u32 qwc) {
 		else
 			qwc = std::min(qwc, 8u);
 	}
-	uint size = gifUnit.TransferGSPacketData(GIF_TRANS_DMA, (u8*)pMem, qwc*16) / 16;
+	uint size;
+	if (CHECK_GIFFIFOHACK) {
+		size = gif_fifo.write(pMem, qwc);
+	}
+	else {
+		size = gifUnit.TransferGSPacketData(GIF_TRANS_DMA, (u8*)pMem, qwc * 16) / 16;
+	}
 	incGifChAddr(size);
 	return size;
 }
@@ -194,12 +311,15 @@ static __fi tDMA_TAG* ReadTag2()
 
 bool CheckPaths(EE_EventType Channel) {
 	// Can't do Path 3, so try dma again later...
-	if(!gifUnit.CanDoPath3()) {
+	if (!CHECK_GIFFIFOHACK) {
-		if(!gifUnit.Path3Masked())
+		if (!gifUnit.CanDoPath3()) {
-		{
+			if (!gifUnit.Path3Masked())
-			CPU_INT(Channel, 128);
+			{
+				GIF_LOG("Path3 stalled");
+				CPU_INT(Channel, 128);
+			}
+			return false;
 		}
-		return false;
 	}
 	return true;
 }
@@ -232,7 +352,7 @@ void GIFdma()
         if (ptag == NULL) return;
 		//DevCon.Warning("GIF Reading Tag MSK = %x", vif1Regs.mskpath3);
 		GIF_LOG("gifdmaChain %8.8x_%8.8x size=%d, id=%d, addr=%lx tadr=%lx", ptag[1]._u32, ptag[0]._u32, gifch.qwc, ptag->ID, gifch.madr, gifch.tadr);
-		gifRegs.stat.FQC = std::min((u16)0x10, gifch.qwc);// FQC=31, hack ;) (for values of 31 that equal 16) [ used to be 0xE00; // APATH=3]
+		if (!CHECK_GIFFIFOHACK)gifRegs.stat.FQC = std::min((u16)0x10, gifch.qwc);// FQC=31, hack ;) (for values of 31 that equal 16) [ used to be 0xE00; // APATH=3]
 		if (dmacRegs.ctrl.STD == STD_GIF)
 		{
 			// there are still bugs, need to also check if gifch.madr +16*qwc >= stadr, if not, stall
@@ -259,7 +379,7 @@ void GIFdma()
 	}
 
 	clearFIFOstuff(true);
-	gifRegs.stat.FQC = std::min((u16)0x10, gifch.qwc);// FQC=31, hack ;) (for values of 31 that equal 16) [ used to be 0xE00; // APATH=3]
+	if (!CHECK_GIFFIFOHACK)gifRegs.stat.FQC = std::min((u16)0x10, gifch.qwc);// FQC=31, hack ;) (for values of 31 that equal 16) [ used to be 0xE00; // APATH=3]
 
 #if USE_OLD_GIF == 1 // ...
 	if (vif1Regs.mskpath3 || gifRegs.mode.M3R) {	
@@ -276,7 +396,7 @@ void GIFdma()
 	// Transfer Dn_QWC from Dn_MADR to GIF
 	if (gifch.qwc > 0) // Normal Mode
 	{
-		gifRegs.stat.FQC = std::min((u16)0x10, gifch.qwc);// FQC=31, hack ;) (for values of 31 that equal 16) [ used to be 0xE00; // APATH=3]
+		if (!CHECK_GIFFIFOHACK)gifRegs.stat.FQC = std::min((u16)0x10, gifch.qwc);// FQC=31, hack ;) (for values of 31 that equal 16) [ used to be 0xE00; // APATH=3]
 
 		if (!CheckPaths(DMAC_GIF)) return;
 
@@ -287,7 +407,7 @@ void GIFdma()
 
 	prevcycles = 0;
 	CPU_INT(DMAC_GIF, gscycles);
-	gifRegs.stat.FQC = std::min((u16)0x10, gifch.qwc);// FQC=31, hack ;) (for values of 31 that equal 16) [ used to be 0xE00; // OPH=1 | APATH=3]
+	if (!CHECK_GIFFIFOHACK)gifRegs.stat.FQC = std::min((u16)0x10, gifch.qwc);// FQC=31, hack ;) (for values of 31 that equal 16) [ used to be 0xE00; // OPH=1 | APATH=3]
 }
 
 void dmaGIF()
@@ -298,7 +418,7 @@ void dmaGIF()
 
 	gspath3done = false; // For some reason this doesn't clear? So when the system starts the thread, we will clear it :)
 
-	gifRegs.stat.FQC |= 0x10; // hack ;)
+	if (!CHECK_GIFFIFOHACK)gifRegs.stat.FQC |= 0x10; // hack ;)
 
 	if (gifch.chcr.MOD == NORMAL_MODE) { //Else it really is a normal transfer and we want to quit, else it gets confused with chains
 		gspath3done = true;
@@ -437,7 +557,7 @@ void mfifoGIFtransfer(int qwc)
 	tDMA_TAG *ptag;
 	mfifocycles = 0;
 	gifmfifoirq = false;
-
+	DevCon.Warning("GIF MFIFO");
 	if (qwc > 0 ) {
 		if ((gifstate & GIF_STATE_EMPTY)) {
 			if(gifch.chcr.STR && !(cpuRegs.interrupt & (1<<DMAC_MFIFO_GIF)))
@@ -606,4 +726,5 @@ void SaveStateBase::gifDmaFreeze() {
 	Freeze(gifqwc);
 	Freeze(gspath3done);
 	Freeze(gscycles);
+	Freeze(gif_fifo);
 }

pcsx2/Gif.h

@@ -93,6 +93,20 @@ enum gifstate_t {
 	GIF_STATE_EMPTY = 0x10
 };
 
+struct GIF_Fifo
+{
+	unsigned int data[64]; //16 QW FIFO
+	unsigned int readdata[64]; //16 QW Inline for reading
+	int readpos, writepos;
+
+	int write(u32* pMem, int size);
+	int read(bool calledFromDMA = false);
+
+	void init();
+};
+
+extern GIF_Fifo gif_fifo;
+
 union tGIF_CTRL
 {
 	struct {

pcsx2/Gif_Unit.h

@@ -593,6 +593,9 @@ struct Gif_Unit {
 				}
 				//DevCon.WriteLn("Adding GS Packet for path %d", stat.APATH);
 				AddCompletedGSPacket(gsPack, (GIF_PATH)(stat.APATH-1));
+				/*if (path.curSize == path.curOffset)
+					curPath = 0;*/
+				
 			}
 
 			if (!gsSIGNAL.queued && !gifPath[0].isDone()) {
@@ -650,13 +653,13 @@ struct Gif_Unit {
 	bool CanDoPath2HL() const {
 		return (stat.APATH == 0 || stat.APATH == 2) && CanDoGif();
 	}
-	// Gif DMA - CHECK_GIFREVERSEHACK is a hack for Hot Wheels.
+	// Gif DMA
 	bool CanDoPath3() const {
 		return((stat.APATH == 0 && !Path3Masked()) || stat.APATH == 3) && CanDoGif();
 	}
 
 	bool CanDoP3Slice()const { return stat.IMT == 1 && gifPath[GIF_PATH_3].state == GIF_PATH_IMAGE; }
-	bool CanDoGif() const    { return stat.PSE == 0 && (CHECK_GIFREVERSEHACK ? 1 : stat.DIR == 0) && gsSIGNAL.queued == 0; }
+	bool CanDoGif() const    { return stat.PSE == 0 && stat.DIR == 0 && gsSIGNAL.queued == 0; }
 	//Mask stops the next packet which hasnt started from transferring
 	bool Path3Masked() const { return ((stat.M3R || stat.M3P) && (gifPath[GIF_PATH_3].state == GIF_PATH_IDLE || gifPath[GIF_PATH_3].state == GIF_PATH_WAIT)); }
 

pcsx2/Hw.cpp

@@ -72,7 +72,7 @@ void hwReset()
 	ipuReset();
 	vif0Reset();
 	vif1Reset();
-
+	gif_fifo.init();
 	// needed for legacy DMAC
 	ipuDmaReset();
 }

pcsx2/HwRead.cpp

@@ -185,14 +185,14 @@ mem32_t __fastcall _hwRead32(u32 mem)
 	if(mem == (D1_CHCR + 0x10) && CHECK_VIFFIFOHACK) 
 		return psHu32(mem) + (vif1ch.qwc * 16);
 
-	if((mem == GIF_CHCR) && !vif1ch.chcr.STR && gifRegs.stat.M3P && gifRegs.stat.APATH != 3)
+	/*if((mem == GIF_CHCR) && !vif1ch.chcr.STR && gifRegs.stat.M3P && gifRegs.stat.APATH != 3)
 	{
 		//Hack for Wallace and Gromit Curse Project Zoo - Enabled the mask, then starts a new
 		//GIF DMA, the mask never comes off and it won't proceed until this is unset.
 		//Unsetting it works too but messes up other PATH3 games.
 		//If STR is already unset, it won't make the slightest difference.
 		return (psHu32(mem) & ~0x100);
-	}
+	}*/
 	return psHu32(mem);
 }
 

pcsx2/Pcsx2Config.cpp

@@ -249,7 +249,7 @@ const wxChar *const tbl_GamefixNames[] =
 	L"DMABusy",
 	L"VIFFIFO",
 	L"VIF1Stall",
-	L"GIFReverse",
+	L"GIFFIFO",
 	L"FMVinSoftware",
 	L"GoemonTlb",
 	L"ScarfaceIbit"
@@ -312,7 +312,7 @@ void Pcsx2Config::GamefixOptions::Set( GamefixId id, bool enabled )
 		case Fix_DMABusy:		DMABusyHack			= enabled;  break;
 		case Fix_VIFFIFO:		VIFFIFOHack			= enabled;  break;
 		case Fix_VIF1Stall:		VIF1StallHack		= enabled;  break;
-		case Fix_GIFReverse:	GIFReverseHack		= enabled;  break;
+		case Fix_GIFFIFO:		GIFFIFOHack			= enabled;  break;
 		case Fix_FMVinSoftware:	FMVinSoftwareHack	= enabled;  break;
 		case Fix_GoemonTlbMiss: GoemonTlbHack		= enabled;  break;
 		case Fix_ScarfaceIbit:  ScarfaceIbit        = enabled;  break;
@@ -338,7 +338,7 @@ bool Pcsx2Config::GamefixOptions::Get( GamefixId id ) const
 		case Fix_DMABusy:		return DMABusyHack;
 		case Fix_VIFFIFO:		return VIFFIFOHack;
 		case Fix_VIF1Stall:		return VIF1StallHack;
-		case Fix_GIFReverse:	return GIFReverseHack;
+		case Fix_GIFFIFO:		return GIFFIFOHack;
 		case Fix_FMVinSoftware:	return FMVinSoftwareHack;
 		case Fix_GoemonTlbMiss: return GoemonTlbHack;
 		case Fix_ScarfaceIbit:  return ScarfaceIbit;
@@ -364,7 +364,7 @@ void Pcsx2Config::GamefixOptions::LoadSave( IniInterface& ini )
 	IniBitBool( DMABusyHack );
 	IniBitBool( VIFFIFOHack );
 	IniBitBool( VIF1StallHack );
-	IniBitBool( GIFReverseHack );
+	IniBitBool( GIFFIFOHack );
 	IniBitBool( FMVinSoftwareHack );
 	IniBitBool( GoemonTlbHack );
 	IniBitBool( ScarfaceIbit );

pcsx2/Vif_Codes.cpp

@@ -220,29 +220,7 @@ vifOp(vifCode_FlushA) {
 			vif1.vifstalled.value = VIF_TIMING_BREAK;
 			return 0;
 			
-			//gifUnit.PrintInfo();
-			/*if (p3.state != GIF_PATH_IDLE && !p1or2) { // Only path 3 left...
-				GUNIT_WARN("Vif FlushA - Getting path3 to finish!");
-				if (gifUnit.lastTranType == GIF_TRANS_FIFO
-				&&  p3.state != GIF_PATH_IDLE && !p3.hasDataRemaining()) { 
-					//p3.state= GIF_PATH_IDLE; // Does any game need this anymore?
-					DevCon.Warning("Vif FlushA - path3 has no more data, but didn't EOP");
-				}
-
-				if (p3.state != GIF_PATH_IDLE) {
-					doStall = true; // If path3 still isn't finished...
-				}
-			}
-			else doStall = true;*/
 		}
-		/*if (doStall) {
-			vif1Regs.stat.VGW = true;
-			vifX.vifstalled.enabled   = VifStallEnable(vifXch);
-			vifX.vifstalled.value = VIF_TIMING_BREAK;
-			return 0;
-		}
-		else*/ 
-		//Didn't need to stall!
 		vif1.cmd = 0;
 		vif1.pass = 0;
 	}
@@ -432,7 +410,9 @@ vifOp(vifCode_MskPath3) {
 		if(!vif1Regs.mskpath3) {
 			//if(!gifUnit.gifPath[GIF_PATH_3].isDone() || gifRegs.stat.P3Q || gifRegs.stat.IP3) {
 				GUNIT_WARN("Path3 triggering!");
-				gifInterrupt();
+				if(CHECK_GIFFIFOHACK)gif_fifo.read(false);
+				else gifInterrupt();
+				GIF_LOG("GIF state on mskpth3 QWC in fifo %x APATH = %x OPH = %x state = %x", gifRegs.stat.FQC, gifRegs.stat.APATH, gifRegs.stat.OPH, gifUnit.gifPath[GIF_PATH_3].state);
 			//}
 		}
 		vif1.cmd = 0;
@@ -457,7 +437,7 @@ vifOp(vifCode_Nop) {
 
 		if (GetVifX.vifpacketsize > 1)
 		{
-			if(((data[1] >> 24) & 0x7f) == 0x6) //is mskpath3 next
+			if(((data[1] >> 24) & 0x7f) == 0x6 && (data[1] & 0x1)) //is mskpath3 next
 			{ 
 				GetVifX.vifstalled.enabled   = VifStallEnable(vifXch);
 				GetVifX.vifstalled.value = VIF_TIMING_BREAK;

pcsx2/gui/Panels/GameFixesPanel.cpp

@@ -93,7 +93,7 @@ Panels::GameFixesPanel::GameFixesPanel( wxWindow* parent )
 			wxEmptyString
 		},
 		{
-			_("Ignore Bus Direction on Path3 Transfer - Used for Hotwheels"),
+			_("Enable the GIF FIFO (slower but needed for Hotwheels, Wallace & Gromit, DJ Hero)"),
 			wxEmptyString
 		},
 		{