Vulkan Device Chooser Layer

This is a Vulkan layer that forces 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

Compiling should only require the Rust toolchain. Build with:

cargo build --release

Installation

Copy the compiled library to the path referenced by library_path in vk_dev_chooser.json, and copy the manifest itself into the system's Vulkan layer directory:

sudo cp target/release/libvk_dev_chooser.so /usr/lib64/libvk_dev_chooser.so
sudo cp vk_dev_chooser.json /usr/share/vulkan/implicit_layer.d/

---

Usage

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.

Additional Selection Options

VULKAN_DEVICE_INDEX also accepts:

• name:<substring> to match a device by name instead of index
• letmechoose to pick the device from a popup window at launch (relies on zenity or kdialog, which can be chosen with VULKAN_DEVICE_CHOOSER_GUI)
• letmechoose:<family> to do the same but remember the choice for that family afterward

---

Steam Launch Options

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%

Credits

Rewritten in Rust, with inspiration from vkdevicechooser.