From 8aca0fe288ff596824f35841826bf8ca90222bef Mon Sep 17 00:00:00 2001
From: refractionpcsx2 <refraction@gmail.com>
Date: Thu, 19 Mar 2026 10:26:30 +0000
Subject: [PATCH] VIF/MFIFO: Respect MFIFO empty condition on SPR transfers

---
 pcsx2/Dmac.h  |  2 +-
 pcsx2/Hw.cpp  | 15 +++++----------
 pcsx2/SPR.cpp | 16 +++-------------
 3 files changed, 9 insertions(+), 24 deletions(-)

diff --git a/pcsx2/Dmac.h b/pcsx2/Dmac.h
index 6ce8924e51..9934a68ed4 100644
--- a/pcsx2/Dmac.h
+++ b/pcsx2/Dmac.h
@@ -561,7 +561,7 @@ extern void hwDmacIrq(int n);
 
 extern void FireMFIFOEmpty();
 extern bool hwMFIFOWrite(u32 addr, const u128* data, uint size_qwc);
-extern void hwMFIFOResume(u32 transferred);
+extern void hwMFIFOResume();
 extern void hwDmacSrcTadrInc(DMACh& dma);
 extern bool hwDmacSrcChainWithStack(DMACh& dma, int id);
 extern bool hwDmacSrcChain(DMACh& dma, int id);
diff --git a/pcsx2/Hw.cpp b/pcsx2/Hw.cpp
index 7019ecb6e3..6f8759fc9f 100644
--- a/pcsx2/Hw.cpp
+++ b/pcsx2/Hw.cpp
@@ -151,18 +151,13 @@ __ri bool hwMFIFOWrite(u32 addr, const u128* data, uint qwc)
 	return true;
 }
 
-__ri void hwMFIFOResume(u32 transferred) {
-
-	if (transferred == 0)
-	{
-		return; //Nothing got put in the MFIFO, we don't care
-	}
+__ri void hwMFIFOResume() {
 
 	switch (dmacRegs.ctrl.MFD)
 	{
 		case MFD_VIF1: // Most common case.
 		{
-			SPR_LOG("Added %x qw to mfifo, Vif CHCR %x Stalled %x done %x", transferred, vif1ch.chcr._u32, vif1.vifstalled.enabled, vif1.done);
+			SPR_LOG("Resuming VIF1 MFIFO, Vif CHCR %x Stalled %x done %x", vif1ch.chcr._u32, vif1.vifstalled.enabled, vif1.done);
 			if (vif1.inprogress & 0x10)
 			{
 				vif1.inprogress &= ~0x10;
@@ -171,7 +166,7 @@ __ri void hwMFIFOResume(u32 transferred) {
 				{
 					SPR_LOG("Data Added, Resuming");
 					//Need to simulate the time it takes to copy here, if the VIF resumes before the SPR has finished, it isn't happy.
-					CPU_INT(DMAC_MFIFO_VIF, transferred * BIAS);
+					CPU_INT(DMAC_MFIFO_VIF, cpuRegs.eCycle[DMAC_FROM_SPR]);
 				}
 
 				//Apparently this is bad, i guess so, the data is going to memory rather than the FIFO
@@ -181,9 +176,9 @@ __ri void hwMFIFOResume(u32 transferred) {
 		}
 		case MFD_GIF:
 		{
-			SPR_LOG("Added %x qw to mfifo, Gif CHCR %x done %x", transferred, gifch.chcr._u32, gif.gspath3done);
+			SPR_LOG("Resuming GIF MFIFO, Gif CHCR %x done %x", gifch.chcr._u32, gif.gspath3done);
 			if ((gif.gifstate & GIF_STATE_EMPTY)) {
-				CPU_INT(DMAC_MFIFO_GIF, transferred * BIAS);
+				CPU_INT(DMAC_MFIFO_GIF, cpuRegs.eCycle[DMAC_FROM_SPR]);
 				gif.gifstate = GIF_STATE_READY;
 			}
 			break;
diff --git a/pcsx2/SPR.cpp b/pcsx2/SPR.cpp
index f92a2b0a6d..f45f096106 100644
--- a/pcsx2/SPR.cpp
+++ b/pcsx2/SPR.cpp
@@ -9,7 +9,7 @@
 
 static bool spr0finished = false;
 static bool spr1finished = false;
-static u32 mfifotransferred = 0;
+static u32 mfifotransferred = 0; // FIXME: Remove next time someone bumps savestates, no longer required.
 
 static void TestClearVUs(u32 madr, u32 qwc, bool isWrite)
 {
@@ -122,8 +122,6 @@ int  _SPR0chain()
 
 			if ((spr0ch.madr & ~dmacRegs.rbsr.RMSK) != dmacRegs.rbor.ADDR)
 				Console.WriteLn("SPR MFIFO Write outside MFIFO area");
-			else
-				mfifotransferred += partialqwc;
 
 			hwMFIFOWrite(spr0ch.madr, &psSu128(spr0ch.sadr), partialqwc);
 			spr0ch.madr += partialqwc << 4;
@@ -198,7 +196,6 @@ void _SPR0interleave()
 			case MFD_VIF1:
 			case MFD_GIF:
 				hwMFIFOWrite(spr0ch.madr, &psSu128(spr0ch.sadr), spr0ch.qwc);
-				mfifotransferred += spr0ch.qwc;
 				break;
 
 			case NO_MFD:
@@ -307,24 +304,17 @@ void SPRFROMinterrupt()
 
 		// The qwc check is simply because having data still to transfer from the packet can freak games out if they do a d.tadr == s.madr check
 		// and there is still data to come over (FF12 ingame menu)
-		if(mfifotransferred != 0 && spr0ch.qwc == 0)
+		if(spr0ch.qwc == 0)
 		{
 			switch (dmacRegs.ctrl.MFD)
 			{
 				case MFD_VIF1: // Most common case.
 				case MFD_GIF:
-				{
-					if ((spr0ch.madr & ~dmacRegs.rbsr.RMSK) != dmacRegs.rbor.ADDR) Console.WriteLn("GIF MFIFO Write outside MFIFO area");
-					spr0ch.madr = dmacRegs.rbor.ADDR + (spr0ch.madr & dmacRegs.rbsr.RMSK);
-					//Console.WriteLn("mfifoGIFtransfer %x madr %x, tadr %x", gif->chcr._u32, gif->madr, gif->tadr);
-					hwMFIFOResume(mfifotransferred);
+					hwMFIFOResume();
 					break;
-				}
 				default:
 					break;
 			}
-
-			mfifotransferred = 0;
 		}
 
 		return;