On Mon, Apr 3, 2017 at 12:56 PM, Keith Packard <keithp@keithp.com> wrote:

Chad Versace <chadversary@chromium.org> writes:

> The real path forward should be implemented on top of
> VK_KHX_external_memory. If you want to start experimenting now with
> Vulkan+KMS, you may want to look at
> VK_EXTERNAL_MEMORY_HANDLE_OPAQUE_FD_KHX.

It seems like the Vulkan spec for WSI with devices has a bunch of what I
would need to implement in a standard fashion; I guess I'm unclear
whether I should go down the route of wrapping all of DRM/KMS in a WSI
layer, or use some of this lower-level stuff directly from the
application instead?

Interesting question. To my knowledge, no one has actually implemented the Vulkan WSI direct-to-display extensions. (I tried to prevent them from getting released with 1.0 but failed.) I believe the correct answer is to use the external memory dma-buf stuff that chad and I have been using and talk directly to KMS. I see no good reason to have a large abstraction in the middle. dma-buf + KMS should give you Intel and radeon (with radv) so that's most of it. In particular, it will give you 100% of people who actually care about DRM leases. :-)