Prior to the X.Org X server version 1.20.7, it is not possibleto enumerate multiple devices if one of them will be used topresent to an X11 swapchain. It is still possible to enumeratemultiple devices even if one of them is driving an X screen, if thedevices will be used for Vulkan offscreen rendering or presentingto a display swapchain. For that, make sure that the applicationcannot open a display connection to an X server by, for example,unsetting the DISPLAY environment variable.