Prefer RT-capable GPUs in adapter ranking for multi-GPU systems

Author: MarkEHenderson

src/dxvk/dxvk_adapter.h

@@ -299,7 +299,7 @@ namespace dxvk {
      * and general troubleshooting.
      */
     void logAdapterInfo() const;
-    
+
     /**
      * \brief Checks whether this is a UMA system
      *
@@ -308,9 +308,19 @@ namespace dxvk {
      * \returns \c true if the system has unified memory.
      */
     bool isUnifiedMemoryArchitecture() const;
-    
 
     // NV-DXVK start: Device filtering
+
+    /**
+     * \brief Checks whether a device extension is supported
+     *
+     * \param [in] pName Extension name
+     * \returns \c true if the extension is supported
+     */
+    bool supportsExtension(const char* pName) const {
+      return m_deviceExtensions.supports(pName) != 0;
+    }
+
     /**
      * \brief Checks if adapter is emulated
      *

src/dxvk/dxvk_instance.cpp

@@ -910,7 +910,20 @@ namespace dxvk {
           if (b->deviceProperties().deviceType == deviceTypes[i]) bRank = i;
         }
 
-        return aRank < bRank;
+        if (aRank != bRank)
+          return aRank < bRank;
+
+        // Among adapters of the same device type, prefer ones that support
+        // ray tracing extensions required by RTX Remix.
+        const bool aSupportsRT = a->supportsExtension(VK_KHR_RAY_QUERY_EXTENSION_NAME)
+                               && a->supportsExtension(VK_KHR_ACCELERATION_STRUCTURE_EXTENSION_NAME);
+        const bool bSupportsRT = b->supportsExtension(VK_KHR_RAY_QUERY_EXTENSION_NAME)
+                               && b->supportsExtension(VK_KHR_ACCELERATION_STRUCTURE_EXTENSION_NAME);
+
+        if (aSupportsRT != bSupportsRT)
+          return aSupportsRT;
+
+        return false;
       });
 
     if (result.size() == 0) {