vkEnumeratePhysicalDevices shows only one of two installed GPUs but that one twice


I have two GPUs installed in my system, a 780 Ti and a 1080 Ti, with the 780 being the primary one with two displays attached. I’d like to use the 1080 Ti with Vulkan for headless rendering, but as the title suggest, it’s not enumerated.

I’m running Arch Linux with the latest versions of everything (nvidia 381.22 and vulkan 1.0.51).

What I tried:

  • nvidia-settings shows both GPUs.
  • Also with CUDA both can be used.
  • Attaching the displays to the 1080 instead of the 780 turns it around and only the 1080 is shown.

I tried several more things, but nothing worked. Do you have any suggestions as to what might be wrong, or is this a driver issue?

Thanks for your help and cheers


thank you for your report. We have filed an internal bug to track this issue.