[dxgi] Add emulateUMA option

Some games think we are on Intel given a lack of NVAPI or AGS/atiadlxx support. Report our device memory as shared memory, and some small amount for a "carveout".

dxvk.conf

@@ -58,6 +58,15 @@
 # dxgi.maxSharedMemory = 0
 
 
+# Some games think we are on Intel given a lack of NVAPI or
+# AGS/atiadlxx support. Report our device memory as shared memory,
+# and some small amount for a "carveout".
+
+# Supported values: True, False
+
+# dxgi.emulateUMA = False
+
+
 # Override back buffer count for the Vulkan swap chain.
 # Setting this to 0 or less will have no effect.
 #

src/dxgi/dxgi_adapter.cpp

@@ -283,6 +283,15 @@ namespace dxvk {
       else
         sharedMemory += heap.size;
     }
+
+    // Some games think we are on Intel given a lack of
+    // NVAPI or AGS/atiadlxx support.
+    // Report our device memory as shared memory,
+    // and some small amount for the carveout.
+    if (options->emulateUMA && !m_adapter->isUnifiedMemoryArchitecture()) {
+      sharedMemory = deviceMemory;
+      deviceMemory = 128 * (1 << 20);
+    }
     
     // Some games are silly and need their memory limited
     if (options->maxDeviceMemory > 0

src/dxgi/dxgi_options.cpp

@@ -32,6 +32,9 @@ namespace dxvk {
     this->customVendorId = parsePciId(config.getOption<std::string>("dxgi.customVendorId"));
     this->customDeviceId = parsePciId(config.getOption<std::string>("dxgi.customDeviceId"));
     this->customDeviceDesc = config.getOption<std::string>("dxgi.customDeviceDesc", "");
+
+    // Emulate a UMA device
+    this->emulateUMA = config.getOption<bool>("dxgi.emulateUMA", false);
     
     // Interpret the memory limits as Megabytes
     this->maxDeviceMemory = VkDeviceSize(config.getOption<int32_t>("dxgi.maxDeviceMemory", 0)) << 20;

src/dxgi/dxgi_options.h

@@ -30,6 +30,9 @@ namespace dxvk {
     VkDeviceSize maxDeviceMemory;
     VkDeviceSize maxSharedMemory;
 
+    /// Emulate UMA
+    bool emulateUMA;
+
     /// Enables nvapi workaround
     bool nvapiHack;
   };