Use a condition variable to notify interrupts, fixes stuttering in the dashboard

src/core/kernel/exports/EmuKrnl.h

@@ -51,6 +51,8 @@ xbox::PLIST_ENTRY RemoveTailList(xbox::PLIST_ENTRY pListHead);
 
 extern xbox::LAUNCH_DATA_PAGE DefaultLaunchDataPage;
 extern xbox::PKINTERRUPT EmuInterruptList[MAX_BUS_INTERRUPT_LEVEL + 1];
+inline std::condition_variable g_InterruptSignal;
+inline std::atomic_bool g_AnyInterruptAsserted = false;
 
 class HalSystemInterrupt {
 public:
@@ -61,6 +63,8 @@ public:
 		}
 
 		m_Asserted = state;
+		g_AnyInterruptAsserted = true;
+		g_InterruptSignal.notify_one();
 	};
 
 	void Enable() {

src/core/kernel/init/CxbxKrnl.cpp

@@ -336,17 +336,6 @@ void InitSoftwareInterrupts()
 }
 #endif
 
-void TriggerPendingConnectedInterrupts()
-{
-	for (int i = 0; i < MAX_BUS_INTERRUPT_LEVEL; i++) {
-		// If the interrupt is pending and connected, process it
-		if (HalSystemInterrupts[i].IsPending() && EmuInterruptList[i] && EmuInterruptList[i]->Connected) {
-			HalSystemInterrupts[i].Trigger(EmuInterruptList[i]);
-		}
-		SwitchToThread();
-	}
-}
-
 static xbox::void_xt NTAPI CxbxKrnlInterruptThread(xbox::PVOID param)
 {
 	CxbxSetThreadName("CxbxKrnl Interrupts");
@@ -355,11 +344,17 @@ static xbox::void_xt NTAPI CxbxKrnlInterruptThread(xbox::PVOID param)
 	InitSoftwareInterrupts();
 #endif
 
+	std::mutex m;
+	std::unique_lock<std::mutex> lock(m);
 	while (true) {
-		if (g_bEnableAllInterrupts) {
-			TriggerPendingConnectedInterrupts();
+		for (int i = 0; i < MAX_BUS_INTERRUPT_LEVEL; i++) {
+			// If the interrupt is pending and connected, process it
+			if (HalSystemInterrupts[i].IsPending() && EmuInterruptList[i] && EmuInterruptList[i]->Connected) {
+				HalSystemInterrupts[i].Trigger(EmuInterruptList[i]);
+			}
 		}
-		Sleep(1);
+		g_InterruptSignal.wait(lock, []() { return g_AnyInterruptAsserted.load() && g_bEnableAllInterrupts.load(); });
+		g_AnyInterruptAsserted = false;
 	}
 
 	assert(0);

src/devices/video/nv2a.cpp

@@ -150,8 +150,6 @@ static void update_irq(NV2AState *d)
 	else {
 		HalSystemInterrupts[3].Assert(false);
 	}
-
-	SwitchToThread();
 }
 
 
@@ -1117,7 +1115,7 @@ static void nv2a_vblank_thread(NV2AState *d)
 			//NV2ADevice::UpdateHostDisplay(d);
 		}
 
-        Sleep(1);
+        std::this_thread::sleep_for(std::chrono::milliseconds(1));
 	}
 }