Vulkan WSI+VK_KHR_display for KMS/DRM?

[Michel Dänzer]

On 04/04/17 11:45 PM, Jason Ekstrand wrote:
> On Mon, Apr 3, 2017 at 12:56 PM, Keith Packard <keithp at keithp.com
> <mailto:keithp at keithp.com>> wrote:
> 
>     Chad Versace <chadversary at chromium.org
>     <mailto:chadversary at 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. :-)

FWIW, there's no fundamental reason why this couldn't work with AMD's
Vulkan driver (currently only available as part of the amdgpu-pro stack)
either.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer