Ubuntu 22.04. I set VK_LAYER_PATH in /etc/enviroment like VK_LAYER_PATH=/etc/vulkan/implicit_layer.d where stored single json file with AMDVLK (need for test). But when I check vulkaninfo, it says that I still have 10 layers (without VK_LAYER_PATH vulkaninfo shows me 12 layers) , among them, as example, MangoHUD. I know where MangoHUD stored its layer json file. This is totally different folder (/usr/share/vulkan/**). From documentation I see "Setting the VK_LAYER_PATH environment variable overrides the default loader layer search mechanism. When set, the loader will search only the directory(s) identified by the VK_LAYER_PATH environment variable for layer manifest files." But it looks like Loader still goes through all default folders to look json files.
Found information that VK_LAYER_PATH only override explicit layers. Implicit will be still looked by default folders. Is it correct? If yes, do we have any option to override implicit search path?
You've probably already found the Loader Layer Interface doc and others like it in the same folder.
Since the loading of implicit layers is supposed to be automatic, I don't think that there is a way to set a search path just for implicit layers by design. You could post a question to the same Vulkan-Loader repo to get a better opinion.
If your goal is to prevent the loading of a set of implicit layers in order to test your own implicit layer by itself, then you can disable implicit layers one by one. Each layer manifest specifies an environment variable that can be set to disable that layer.