Evaluate DLSS-RR through NGX independently from DLSS-G through streamline

[pborsutzki]

Hi,

I am trying to extend a vulkan application with frame generation. The application already has an integration of DLSS-RR through the NGX interface. I do not intend to replace the NGX integration with streamline as the application needs deployment on linux (where I can rather pass on frame generation, but not on ray reconstruction).

As I currently cannot see a way to get frame pacing with frame generation when using the frame generation interface from NGX, I concluded that I currently have to use streamline for this task. As my rendering architecture is plugin based, rendering of images and their presentation to the screen is completely separated. It is a plugin renderer based on vulkan that is integrated into multiple applications that have different UIs on top - these UIs are rendered and presented from dx11, gl and vulkan. So the streamline integration will be a part of the ui application level.

Now, when enabling DLSS-RR in the renderer plugin, and then enabling DLSS-G from streamline in the application I get this error spammed into cout (and frame generation refuses to work):

[2025-12-11 09:40:43] [tid:40116][DLSSGInstanceManager::InferDevice:557] Error: multiple active devices present, and a device was not specified
[09-40-43][streamline][error][tid:40116][32s:846ms:767us]commonEntry.cpp:596[createNGXFeature] NVSDK_NGX_VULKAN_CreateFeature((VkCommandBuffer)cmdList, feature, ctx.ngxContext.params, handle) failed 0xbad00005

However, when I enable FG first, and DLSS-RR afterwards, it kind of works (until FG is turned off and back on again).

So it seems like these "two" libraries are talking to each other in ways I don't want them to talk. How can I avoid this and use them without conflicting? Always enabling frame generation before DLSS-RR is not really an option.

Thanks for having a look!

---

More integration details:

• The renderer plugin that renders images into buffers:
  • Loads vulkan-1.dll directly dynamically, it does not use the streamline hooks.
  • Loads nvngx_dlssd.dll directly and uses the NGX interfaces.
  • Uses a separate device, queue, etc. from the ui application. The final images are exported from vulkan using opaque system handles and semaphores for synchronization.
  • Does not create a swapchain/surface/etc.
• The ui application that presents images to the screen:
  • Loads all vulkan functions through sl.interposer.dll. The dll is loaded at runtime.
  • Uses the streamline interface to enable frame generation.
  • Uses a separate device, queue, etc. from the renderer
  • Using eUseManualHooking or calling slSetVulkanInfo does not seem to prevent the issue.
  • Does create a swapchain/surface/etc. and uses it to display the rendered images into a window (plus some UI).

I am using an RTX 5000 Ada, a 581.80 driver on Windows 11 Enterprise 23H2 with streamline 2.9.0.

[jake-nv]

Nvbug: 5763191