From a72fa4b9ccabf5113a903f880e7df64e9dffc467 Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Thu, 16 Jun 2022 15:40:41 -0700
Subject: [PATCH] DSPHLE: Don't generate new mail if the DSP is halted

This fixes booting Datel titles with DSPHLE (see https://bugs.dolphin-emu.org/issues/12943). Datel messed up their DSP initialization code, so it only works by receiving a mail later on, but if halting isn't implemented then it receives the mail too early and hangs.
---
 Source/Core/Core/HW/DSPHLE/DSPHLE.cpp      |  1 +
 Source/Core/Core/HW/DSPHLE/MailHandler.cpp | 12 ++++--------
 Source/Core/Core/HW/DSPHLE/MailHandler.h   |  4 +++-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp b/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
index 9e17a78ecc..b8d3b8e5a2 100644
--- a/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
+++ b/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
@@ -196,6 +196,7 @@ u16 DSPHLE::DSP_WriteControlRegister(u16 value)
   {
     INFO_LOG_FMT(DSPHLE, "DSP_CONTROL halt bit changed: {:04x} -> {:04x}", m_dsp_control.Hex,
                  value);
+    m_mail_handler.SetHalted(temp.DSPHalt);
   }
 
   if (temp.DSPReset)
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
index fc5b22b778..f297b6f53c 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
@@ -39,7 +39,7 @@ void CMailHandler::PushMail(u32 mail, bool interrupt, int cycles_into_future)
 u16 CMailHandler::ReadDSPMailboxHigh()
 {
   // check if we have a mail for the CPU core
-  if (!m_pending_mails.empty())
+  if (!m_halted && !m_pending_mails.empty())
   {
     m_last_mail = m_pending_mails.front().first;
   }
@@ -49,7 +49,7 @@ u16 CMailHandler::ReadDSPMailboxHigh()
 u16 CMailHandler::ReadDSPMailboxLow()
 {
   // check if we have a mail for the CPU core
-  if (!m_pending_mails.empty())
+  if (!m_halted && !m_pending_mails.empty())
   {
     m_last_mail = m_pending_mails.front().first;
     const bool generate_interrupt = m_pending_mails.front().second;
@@ -79,13 +79,9 @@ bool CMailHandler::HasPending() const
   return !m_pending_mails.empty();
 }
 
-void CMailHandler::Halt(bool _Halt)
+void CMailHandler::SetHalted(bool halt)
 {
-  if (_Halt)
-  {
-    ClearPending();
-    PushMail(0x80544348);
-  }
+  m_halted = halt;
 }
 
 void CMailHandler::DoState(PointerWrap& p)
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.h b/Source/Core/Core/HW/DSPHLE/MailHandler.h
index c036a9f72d..ee38bcde53 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.h
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.h
@@ -20,7 +20,7 @@ public:
 
   // TODO: figure out correct timing for interrupts rather than defaulting to "immediately."
   void PushMail(u32 mail, bool interrupt = false, int cycles_into_future = 0);
-  void Halt(bool _Halt);
+  void SetHalted(bool halt);
   void DoState(PointerWrap& p);
   bool HasPending() const;
 
@@ -42,5 +42,7 @@ private:
   // If no pending mail exists, the last mail that was read is returned,
   // but with the top bit (0x80000000) cleared.
   u32 m_last_mail = 0;
+  // When halted, the DSP itself is not running, but the last mail can be read.
+  bool m_halted = false;
 };
 }  // namespace DSP::HLE