Vulkan Device Chooser Layer

This is a quick and dirty implementation of a Vulkan layer to force a specific physical device to be used. This is useful for Vulkan games which do not provide an option to choose the device themselves.

Compiling requires vulkan/vulkan.h, vulkan/vk_layer.h and vulkan/vk_layer_dispatch_table.h. On Debian based systems, you can install these with:

sudo apt-get install libvulkan-dev vulkan-validationlayers-dev

On Fedora, you can install these with:

sudo dnf install vulkan-headers vulkan-validation-layers-devel

Build and install with:

meson builddir --prefix=/usr
meson compile -C builddir
sudo meson install -C builddir

This will install to the system's Vulkan layer directory, /usr/share/vulkan/implicit_layer.d/.

To run a Vulkan application forcing a specific device to be used, launch it with these environment variables:

ENABLE_DEVICE_CHOOSER_LAYER=1 VULKAN_DEVICE_INDEX=<device index>

Replace <device index> with the "GPU id" for the desired device as reported by vulkaninfo (without the layer enabled).

For example:

$ ENABLE_DEVICE_CHOOSER_LAYER=1 VULKAN_DEVICE_INDEX=1 vulkaninfo

should give info for the device which had GPU id 1 when running vulkaninfo without the environment variable set.

The layer can be used with Steam games by setting their launch options to:

ENABLE_DEVICE_CHOOSER_LAYER=1 VULKAN_DEVICE_INDEX=<device index> %command%