How the VK_LAYER_AMD_switchable_graphics is supposed to work?

Discussion created by cospp on Dec 3, 2019
Latest reply on Jan 8, 2020 by zinx

I have a laptop with Intel 620 and extenal RX 580 in Akitio Node Thunderbolt 3 case. When connecting eGPU and running vulkaininfo only the Intel 620 gpu is enumerated and then I get an error: vulkaninfo.h:881: failed with ERROR_INITIALIZATION_FAILED while enumerating device groups.

OS: Windows 10

AMD drivers tried: 19.11.3, 19.9.2, 19.6.2

Vulkaninfo SDK versions: 1.1.126, 1.1.123, 1.1.106 (report the same error at different source locations)


However when setting DISABLE_LAYER_AMD_SWITCHABLE_GRAPHICS_1=1 environment variable both GPUs are reported by vulkaninfo without errors.


I can provide both good and faulty vulkaninfo reports if necessary.


So the question is: Is reporting a single GPU with VK_LAYER_AMD_switchable_graphics is an intended behaviour? If so, I will report the issue to Vulkan Loader developers.

Reporting a single GPU while having multiple usable GPUs seems odd to me, as I can no longer choose GPU in my application as well as use multiple GPUs without settings this variable.

Also both GPUs are enumerated as OpenCL devices with or without setting the variable.

Any other information about VK_LAYER_AMD_switchable_graphics is appreciated (I couldn't find any developer related info)


EDIT: PS: May I have this question posted in appropriate "OpenGL & Vulkan" devs forum?