From 6bc7cf29cc13a5b5b552e05795f502efcc19bca5 Mon Sep 17 00:00:00 2001
From: Albert Liu <45282415+ggrtk@users.noreply.github.com>
Date: Thu, 22 Oct 2020 21:41:42 -0700
Subject: [PATCH] GPU: Synchronize CRTC on GP1(05h) command

Fixes text flashing briefly after startup PlayStation logo in King's
Field (USA).
---
 src/core/gpu.cpp | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/core/gpu.cpp b/src/core/gpu.cpp
index c1f05e737..01ab9c7f8 100644
--- a/src/core/gpu.cpp
+++ b/src/core/gpu.cpp
@@ -964,10 +964,16 @@ void GPU::WriteGP1(u32 value)
 
     case 0x05: // Set display start address
     {
-      m_crtc_state.regs.display_address_start = param & CRTCState::Regs::DISPLAY_ADDRESS_START_MASK;
-      Log_DebugPrintf("Display address start <- 0x%08X", m_crtc_state.regs.display_address_start);
+      const u32 new_value = param & CRTCState::Regs::DISPLAY_ADDRESS_START_MASK;
+      Log_DebugPrintf("Display address start <- 0x%08X", new_value);
+
       System::IncrementInternalFrameNumber();
-      UpdateCRTCDisplayParameters();
+      if (m_crtc_state.regs.display_address_start != new_value)
+      {
+        SynchronizeCRTC();
+        m_crtc_state.regs.display_address_start = new_value;
+        UpdateCRTCConfig();
+      }
     }
     break;