vulkaninfo cannot get info on GPU 1 only

[alexpanter]

Hi,

Unless I completely misunderstand how to use the vulkaninfo tool on the command line, there's something strange afoot here.. If I run the tool without any arguments, I get a list like this:

Layers: count = 4
=================
VK_LAYER_INTEL_nullhw (INTEL NULL HW) Vulkan version 1.1.73, layer version 1:
	Layer Extensions: count = 0
	Devices: count = 3
		GPU id = 0 (AMD Radeon Graphics (RADV REMBRANDT))
		Layer-Device Extensions: count = 0

		GPU id = 1 (NVIDIA GeForce RTX 3070 Ti Laptop GPU)
		Layer-Device Extensions: count = 0

		GPU id = 2 (llvmpipe (LLVM 15.0.7, 256 bits))
		Layer-Device Extensions: count = 0

[...]

According to the help message (vulkaninfo --help) I should be able to get info on a select GPU:

[-j=<gpu-number>, --json=<gpu-number>]
                    For a multi-gpu system, a single gpu can be targetted by
                    specifying the gpu-number associated with the gpu of 
                    interest. This number can be determined by running
                    vulkaninfo without any options specified.

And then I try to run it like this:

vulkaninfo -j=1

-- but I only get the help message, alluring the fact that I'm possibly using the tool in the wrong way. And I do not want a JSON output, but rather text, which is more easily readable.

Platform is Ubuntu 23.04.