The VKMS driver within the Linux kernel allows for virtual kernel mode-setting as a software-only KMS/DRM driver that can be used for virtual testing purposes and other uses around headless systems. New patches out of Google are working on ConfigFS support for this virtual display driver and from there making it easy to build out your own virtual graphics device configuration with VKMS.

With the VKMS patches sent out by Google's Jim Shargo, it's easy to then build new DRM devices with user-defined DRM objects and object relationships by creating / writing / symlinking files.

With the ConfigFS support as the interface for interacting with the VKMS driver for building out new configurations, it's possible to create virtual devices with arbitrary numbers of CRTCs, planes, connectors, and encoders. With ConfigFS, it's just a matter of creating directories, connecting the different objects via symlinking, and then once configured to register the device.

Documentation around the proposed VKMS ConfigFS interface for building out your virtual display configuration.

This opens up VKMS to a lot more configurability in an easy manner and can help in testing more unique DRM device configurations.

See this patch series for more details on the VKMS ConfigFS support being proposed and now under review.