gfxbench app is not using zink driver on Nvidia GPU.

[mayank4519]

I ran gfxbench application on Qualcomm and Nvidia's GPU using zink drivers by setting these env variables.

set GALLIUM_DRIVER=zink
set MESA_LOADER_DRIVER_OVERRIDE=zink
gfxbench.exe

But, on NVIDIA device, app is not displaying OpenGL with Zink Vulkan NVIDIA while on adreno, app is correctly showing OpenGL with Zink Vulkan Adreno.
Does anyone know what's wrong here. Why Nvidia isn't using zink drivers.