From 00c85c4a8fce31ee48d3685ea286d0e4b71e2ee4 Mon Sep 17 00:00:00 2001
From: TJnotJT <tjnotjt.github@gmail.com>
Date: Sat, 18 Apr 2026 08:49:18 -0400
Subject: [PATCH] GS/TC: Use temporary source on invalid TEX0.

---
 pcsx2/GS/GSUtil.cpp                      | 24 ++++++++++++++++++++++++
 pcsx2/GS/GSUtil.h                        |  2 ++
 pcsx2/GS/Renderers/HW/GSTextureCache.cpp |  8 ++++++++
 3 files changed, 34 insertions(+)

diff --git a/pcsx2/GS/GSUtil.cpp b/pcsx2/GS/GSUtil.cpp
index 85be5b0836..ef080e6283 100644
--- a/pcsx2/GS/GSUtil.cpp
+++ b/pcsx2/GS/GSUtil.cpp
@@ -339,3 +339,27 @@ const char* GSUtil::GetPSMName(int psm)
 	}
 	return "BAD_PSM";
 }
+
+bool GSUtil::IsValidPSM(int psm)
+{
+	switch (psm)
+	{
+		case PSMCT32:
+		case PSMCT24:
+		case PSMCT16:
+		case PSMCT16S:
+		case PSMT8:
+		case PSMT4:
+		case PSMT8H:
+		case PSMT4HL:
+		case PSMT4HH:
+		case PSMZ32:
+		case PSMZ24:
+		case PSMZ16:
+		case PSMZ16S:
+		case PSGPU24:
+			return true;
+		default:
+			return false;
+	}
+}
\ No newline at end of file
diff --git a/pcsx2/GS/GSUtil.h b/pcsx2/GS/GSUtil.h
index 90a5ad3048..de600bd9ca 100644
--- a/pcsx2/GS/GSUtil.h
+++ b/pcsx2/GS/GSUtil.h
@@ -28,6 +28,8 @@ public:
 	static const char* GetACName(u32 ac);
 	static const char* GetPerfMonCounterName(GSPerfMon::counter_t counter, bool hw = true);
 
+	static bool IsValidPSM(int psm);
+
 	static const u32* HasSharedBitsPtr(u32 dpsm);
 	static bool HasSharedBits(u32 spsm, const u32* ptr);
 	static bool HasSharedBits(u32 spsm, u32 dpsm);
diff --git a/pcsx2/GS/Renderers/HW/GSTextureCache.cpp b/pcsx2/GS/Renderers/HW/GSTextureCache.cpp
index 0e54849e7b..e065c033db 100644
--- a/pcsx2/GS/Renderers/HW/GSTextureCache.cpp
+++ b/pcsx2/GS/Renderers/HW/GSTextureCache.cpp
@@ -1340,6 +1340,14 @@ GSTextureCache::Source* GSTextureCache::LookupSource(const bool is_color, const
 		return nullptr;
 	}
 
+	// Invalid values show up in dumps but it's unclear if it's a core issue or a bug in the games.
+	// Return a temporary source to prevent the lookup from corrupting the TC.
+	if (TEX0.TBW > 32 && !GSUtil::IsValidPSM(static_cast<int>(TEX0.PSM)))
+	{
+		GL_CACHE("TC: Invalid TEX0 (TBW=%d, PSM=%x), using temporary source.", TEX0.TBW, TEX0.PSM);
+		return CreateSource(TEX0, TEXA, CLAMP, nullptr, 0, 0, nullptr, nullptr, nullptr, SourceRegion(), true);
+	}
+
 	const GSVector2i compare_lod(lod ? *lod : GSVector2i(0, 0));
 	Source* src = nullptr;