Vulkan: only enable host image copy on UMA devices

Author: TheMostDiligent

Graphics/GraphicsEngine/include/RenderDeviceBase.hpp

@@ -73,7 +73,8 @@ DeviceFeatures EnableDeviceFeatures(const DeviceFeatures& SupportedFeatures,
                                     const DeviceFeatures& RequestedFeatures) noexcept(false);
 
 DeviceFeaturesVk EnableDeviceFeaturesVk(const DeviceFeaturesVk& SupportedFeatures,
-                                        const DeviceFeaturesVk& RequestedFeatures) noexcept(false);
+                                        const DeviceFeaturesVk& RequestedFeatures,
+                                        bool                    IsUMA) noexcept(false);
 
 /// Checks sparse texture format support and returns the component type
 COMPONENT_TYPE CheckSparseTextureFormatSupport(TEXTURE_FORMAT                  TexFormat,

Graphics/GraphicsEngine/src/RenderDeviceBase.cpp

@@ -128,12 +128,23 @@ DeviceFeatures EnableDeviceFeatures(const DeviceFeatures& SupportedFeatures,
 }
 
 DeviceFeaturesVk EnableDeviceFeaturesVk(const DeviceFeaturesVk& SupportedFeatures,
-                                        const DeviceFeaturesVk& RequestedFeatures) noexcept(false)
+                                        const DeviceFeaturesVk& RequestedFeatures,
+                                        bool                    IsUMA) noexcept(false)
 {
     DeviceFeaturesVk EnabledFeatures;
 
     ENABLE_FEATURE(DynamicRendering, "VK_KHR_dynamic_rendering is");
-    ENABLE_FEATURE(HostImageCopy, "VK_EXT_host_image_copy is");
+    if (RequestedFeatures.HostImageCopy == DEVICE_FEATURE_STATE_OPTIONAL && SupportedFeatures.HostImageCopy != DEVICE_FEATURE_STATE_DISABLED)
+    {
+        // Only enable VK_EXT_host_image_copy if the device is UMA.
+        // On discrete GPUs, textures with VK_IMAGE_USAGE_HOST_TRANSFER_BIT usage are allocated in a host-visible
+        // device local memory that is very scarce.
+        EnabledFeatures.HostImageCopy = IsUMA ? DEVICE_FEATURE_STATE_ENABLED : DEVICE_FEATURE_STATE_DISABLED;
+    }
+    else
+    {
+        ENABLE_FEATURE(HostImageCopy, "VK_EXT_host_image_copy is");
+    }
 
     ASSERT_SIZEOF(DeviceFeaturesVk, 2, "Did you add a new feature to DeviceFeaturesVk? Please handle its status here (if necessary).");
 

Graphics/GraphicsEngineVulkan/include/VulkanUtilities/VulkanPhysicalDevice.hpp

@@ -129,6 +129,8 @@ class VulkanPhysicalDevice
     VkFormatProperties                          GetPhysicalDeviceFormatProperties(VkFormat imageFormat, VkFormatProperties3* Properties3 = nullptr) const;
     const std::vector<VkQueueFamilyProperties>& GetQueueProperties() const { return m_QueueFamilyProperties; }
 
+    bool IsUMA() const;
+
 private:
     VulkanPhysicalDevice(const CreateInfo& CI);
 

Graphics/GraphicsEngineVulkan/src/EngineFactoryVk.cpp

@@ -754,7 +754,7 @@ void EngineFactoryVkImpl::CreateDeviceAndContextsVk(const EngineVkCreateInfo& En
         VerifyEngineCreateInfo(EngineCI, AdapterInfo);
         const DeviceFeatures   EnabledFeatures   = EnableDeviceFeatures(AdapterInfo.Features, EngineCI.Features);
         const DeviceFeaturesVk AdapterFeaturesVk = PhysicalDeviceFeaturesToDeviceFeaturesVk(PhysicalDevice->GetExtFeatures(), DEVICE_FEATURE_STATE_OPTIONAL);
-        const DeviceFeaturesVk EnabledFeaturesVk = EnableDeviceFeaturesVk(AdapterFeaturesVk, EngineCI.FeaturesVk);
+        const DeviceFeaturesVk EnabledFeaturesVk = EnableDeviceFeaturesVk(AdapterFeaturesVk, EngineCI.FeaturesVk, PhysicalDevice->IsUMA());
 
         std::vector<VkDeviceQueueGlobalPriorityCreateInfoEXT> QueueGlobalPriority;
         std::vector<VkDeviceQueueCreateInfo>                  QueueInfos;

Graphics/GraphicsEngineVulkan/src/VulkanUtilities/VulkanPhysicalDevice.cpp

@@ -566,4 +566,9 @@ VkFormatProperties VulkanPhysicalDevice::GetPhysicalDeviceFormatProperties(VkFor
     }
 }
 
+bool VulkanPhysicalDevice::IsUMA() const
+{
+    return m_MemoryProperties.memoryHeapCount == 1;
+}
+
 } // namespace VulkanUtilities