From 21b5f9262c14114f457120a0504a55fc3ca96489 Mon Sep 17 00:00:00 2001
From: athrxx
Date: Sun, 10 Nov 2019 15:24:41 +0100
Subject: AUDIO: (FM-TOWNS/PC-98) - fix regression from 0e734722

My commit 0e734722 causes lockups in SCUMM (sometimes) and SCI (very often). I didn't like the way I had fixed this before, but in the end I now had to do it in a similar way.
---
 audio/softsynth/fmtowns_pc98/pc98_audio.cpp | 31 ++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

(limited to 'audio/softsynth/fmtowns_pc98/pc98_audio.cpp')

diff --git a/audio/softsynth/fmtowns_pc98/pc98_audio.cpp b/audio/softsynth/fmtowns_pc98/pc98_audio.cpp
index 9ab1ec7659..144e9834b0 100644
--- a/audio/softsynth/fmtowns_pc98/pc98_audio.cpp
+++ b/audio/softsynth/fmtowns_pc98/pc98_audio.cpp
@@ -47,6 +47,7 @@ public:
 	void ssgSetVolume(int volume);
 
 	Common::Mutex &mutex();
+	int mixerThreadLockCounter() const;
 
 private:
 	bool assignPluginDriver(PC98AudioCore *owner, PC98AudioPluginDriver *driver, bool externalMutexHandling = false);
@@ -192,6 +193,10 @@ Common::Mutex &PC98AudioCoreInternal::mutex() {
 	return _mutex;
 }
 
+int PC98AudioCoreInternal::mixerThreadLockCounter() const {
+	return _mixerThreadLockCounter;
+}
+
 bool PC98AudioCoreInternal::assignPluginDriver(PC98AudioCore *owner, PC98AudioPluginDriver *driver, bool externalMutexHandling) {
 	Common::StackLock lock(_mutex);
 	if (_refCount <= 1)
@@ -215,13 +220,11 @@ void PC98AudioCoreInternal::removePluginDriver(PC98AudioCore *owner) {
 }
 
 void PC98AudioCoreInternal::timerCallbackA() {
-	Common::StackLock lock(_mutex);
 	if (_drv && _ready)
 		_drv->timerCallbackA();
 }
 
 void PC98AudioCoreInternal::timerCallbackB() {
-	Common::StackLock lock(_mutex);
 	if (_drv && _ready)
 		_drv->timerCallbackB();
 }
@@ -283,12 +286,30 @@ PC98AudioCore::MutexLock PC98AudioCore::stackLockMutex() {
 	return MutexLock(_internal);
 }
 
-PC98AudioCore::MutexLock::MutexLock(PC98AudioCoreInternal *pc98int) : _pc98int(pc98int) {
-	if (_pc98int)
+PC98AudioCore::MutexLock PC98AudioCore::stackUnlockMutex() {
+	return MutexLock(_internal, _internal->mixerThreadLockCounter());
+}
+
+PC98AudioCore::MutexLock::MutexLock(PC98AudioCoreInternal *pc98int, int reverse) : _pc98int(pc98int), _count(reverse) {
+	if (!_pc98int)
+		return;
+
+	if (!reverse) {
 		_pc98int->mutex().lock();
+		return;
+	}
+
+	while (reverse--)
+		_pc98int->mutex().unlock();
 }
 
 PC98AudioCore::MutexLock::~MutexLock() {
-	if (_pc98int)
+	if (!_pc98int)
+		return;
+
+	if (!_count)
 		_pc98int->mutex().unlock();
+
+	while (_count--)
+		_pc98int->mutex().lock();
 }
-- 
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