Add spoof guide

extra-files/SSDT-GPU-SPOOF.dsl

@@ -0,0 +1,69 @@
+// Based off of WhateverGreen's sample.dsl
+// https://github.com/acidanthera/WhateverGreen/blob/master/Manual/Sample.dsl
+DefinitionBlock ("", "SSDT", 2, "ACDT", "AMDGPU", 0x00001000)
+{
+    External (_SB_.PCI0, DeviceObj)
+    External (_SB_.PCI0.PEG0.PEGP, DeviceObj)
+
+
+    Scope (\_SB.PCI0.PEG0.PEGP)
+    {
+      If (_OSI ("Darwin"))
+      {
+        Method (_DSM, 4, NotSerialized)  // _DSM: Device-Specific Method
+        {
+            Store (Package ()
+            {
+                // Where we shove our FakeID
+                "device-id",
+                Buffer (0x04)
+                {
+                    0xB0, 0x67, 0x00, 0x00
+                },
+
+                // Changing the name of the GPU reported, mainly cosmetic
+                "model",
+                Buffer ()
+                {
+                    "AMD Radeon R9 390"
+                }
+                        
+             }, Local0)
+             DTGP (Arg0, Arg1, Arg2, Arg3, RefOf (Local0))
+             Return (Local0)
+         }
+       }
+    Scope (\_SB.PCI0)
+    {                   
+        Method (DTGP, 5, NotSerialized)
+        {
+            If (LEqual (Arg0, ToUUID ("a0b5b7c6-1318-441c-b0c9-fe695eaf949b")))
+            {
+                If (LEqual (Arg1, One))
+                {
+                    If (LEqual (Arg2, Zero))
+                    {
+                        Store (Buffer (One)
+                            {
+                                 0x03
+                            }, Arg4)
+                        Return (One)
+                    }
+
+                    If (LEqual (Arg2, One))
+                    {
+                        Return (One)
+                    }
+                }
+            }
+
+            Store (Buffer (One)
+                {
+                     0x00
+                }, Arg4)
+            Return (Zero)
+        }
+      }
+    }
+
+}