Vulkan software renderer fallback?

[osnr]

probably lavapipe since it's built-in -- fallback for GPUs where the drivers don't work (nvidia right now, although hopefully we can just fix that) and for virtual machines

[osnr]

think we would need to do the plumbing to have lavapipe render to an in-memory buffer + revive something like the fbdev or libdrm code path that can blit that buffer to the screen (which should work on pretty much any hardware), lavapipe doesn't support the vk display extension that we use for real GPUs