[Mesa-dev] MesaGL <-> non-Mesa OpenCL interop interface

[Marek Olšák]

On Sat, Feb 6, 2016 at 6:53 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> I'm adding Chad to the Cc.  At some point, it would be good to get Beignet
> playing well with mesa.  Personally, I have substantial reservations about
> getting the kernel involved in surface layout for anything more than 2-D
> non-mipmapped non-array surfaces.  Laying them out can be complicated, and
> committing to a stable API, or worse a kernel API seems a bit tricky.  But
> I'll let chad rant about that :-)

Well, the kernel isn't really involved much. We have 2 mechanisms to
set the surface layout:

1) Tiling flags limited to 2D surfaces only. This is how the surface
layout is communicated to the display kernel code and between X and
apps.

2) Opaque metadata. Every buffer has 256 bytes of CPU memory. The
format is opaque to the kernel. It's meant for userspace drivers to
exchange any information about buffers they want, even multiple
allocations/surfaces per buffer, etc. So far the only use case for
this feature is the GL-CL interop.

Marek