> >We could also do it the other way around: Instead of having the kernel
> >the plane description userspace could pass it in, and the kernel throws
> >-EINVAL in
> >case it doesn't match due to things having changed meanwhile.
> Or just return a dmabuf based on the current plane ?
If gvt is able to hand out dma-bufs for inactive planes, then yes, we
can do this. Have one ioctl where we pass in the plane id, get back a
plane description struct, and another where we pass in the plane
description struct and get back a dma-buf fd.