Rough in some stuff for better oninputpoll in snes. Not hooked up in looah yet. The idea is that oninputpoll will get called with a core-specific int that signifies what happened.

For snes, we're looking at:
0 = latch goes low
1 = latch goes high
2 = left port strobed
3 = right port strobed

BizHawk.Emulation.Cores/Consoles/Nintendo/SNES/LibsnesCore.cs

@@ -284,7 +284,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 		private readonly InputCallbackSystem _inputCallbacks = new InputCallbackSystem();
 
 		// TODO: optimize managed to unmanaged using the ActiveChanged event
-		public IInputCallbackSystem InputCallbacks { [FeatureNotImplemented]get { return _inputCallbacks; } }
+		public IInputCallbackSystem InputCallbacks { get { return _inputCallbacks; } }
 
 		public ITraceable Tracer { get; private set; }
 		public IMemoryCallbackSystem MemoryCallbacks { get; private set; }
@@ -501,7 +501,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 		{
 			// as this is implemented right now, only P1 and P2 normal controllers work
 
-			InputCallbacks.Call();
+			// port = 0, oninputpoll = 2: left port was strobed
+			// port = 1, oninputpoll = 3: right port was strobed
+			Console.WriteLine("ONINPUTPOLL: {0}", port + 2);
+
+			// InputCallbacks.Call();
 			//Console.WriteLine("{0} {1} {2} {3}", port, device, index, id);
 
 			string key = "P" + (1 + port) + " ";
@@ -539,7 +543,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 
 		void snes_input_notify(int index)
 		{
-			IsLagFrame = false;
+			// gets called with the following numbers:
+			// 4xxx : lag frame related
+			// 0: signifies latch bit going to 0.  should be reported as oninputpoll
+			// 1: signifies latch bit going to 1.  should be reported as oninputpoll
+			if (index >= 0x4000)
+				IsLagFrame = false;
+			else
+				Console.WriteLine("ONINPUTPOLL: {0}", index);
 		}
 
 		void snes_video_refresh(int* data, int width, int height)

libsnes/bsnes/snes/alt/cpu/mmio.cpp

@@ -132,6 +132,7 @@ void CPU::mmio_write(unsigned addr, uint8 data) {
     case 0x4016: {
       input.port1->latch(data & 1);
       input.port2->latch(data & 1);
+	  interface()->inputNotify(data & 1); // latch notify
 			if (!status.auto_joypad_poll_enabled) { interface()->inputNotify(0x4016); }
       return;
     }

libsnes/bsnes/snes/alt/cpu/timing.cpp

@@ -87,10 +87,14 @@ void CPU::scanline() {
 }
 
 void CPU::run_auto_joypad_poll() {
+	
   input.port1->latch(1);
   input.port2->latch(1);
   input.port1->latch(0);
   input.port2->latch(0);
+  interface()->inputNotify(1);
+  interface()->inputNotify(0);
+
 
   uint16 joy1 = 0, joy2 = 0, joy3 = 0, joy4 = 0;
   for(unsigned i = 0; i < 16; i++) {

libsnes/bsnes/snes/cpu/mmio/mmio.cpp

@@ -35,6 +35,7 @@ void CPU::mmio_w2183(uint8 data) {
 void CPU::mmio_w4016(uint8 data) {
   input.port1->latch(data & 1);
   input.port2->latch(data & 1);
+  interface()->inputNotify(data & 1);
 }
 
 //JOYSER0

libsnes/bsnes/snes/cpu/timing/joypad.cpp

@@ -13,6 +13,8 @@ void CPU::step_auto_joypad_poll() {
         input.port2->latch(1);
         input.port1->latch(0);
         input.port2->latch(0);
+		interface()->inputNotify(1);
+		interface()->inputNotify(0);
       }
 
       uint2 port0 = input.port1->data();