[Mesa-dev] [RFC] New gallium flags for using different contexts in several threads

[Nicolai Hähnle]

On 18.12.2016 13:38, Axel Davy wrote:
> Currently there is no real specification on what is allowed for
> using different contexts in several threads, or when you
> map/unmap a resource in a thread, but uses it in another for
> draw calls.
>
> For the gallium nine CSMT patchset, I've figured out it would be better
> to add flags to describe what is allowed.
>
> Please comment.

I don't see the point of this. All existing drivers must already support 
the multi-threading scenarios described in the commits, because they can 
happen as part of correct use of OpenGL. If drivers don't support them, 
then they're already broken.

I'm happy to be convinced otherwise if I missed something, but using 
multiple contexts from different threads, or using Map/UnmapBuffer from 
one context but sourcing the buffer from draw calls in another context 
are all perfectly supported OpenGL use cases.

Nicolai

>
> Yours,
>
> Axel Davy
>
> Axel Davy (3):
>   gallium: add PIPE_CAP_THREAD_SAFE
>   radeon: enable PIPE_CAP_THREAD_SAFE
>   gallium: add flag for transfers in a different context than draw call
>
>  src/gallium/docs/source/screen.rst               | 12 ++++++++++++
>  src/gallium/drivers/freedreno/freedreno_screen.c |  2 ++
>  src/gallium/drivers/i915/i915_screen.c           |  2 ++
>  src/gallium/drivers/ilo/ilo_screen.c             |  2 ++
>  src/gallium/drivers/llvmpipe/lp_screen.c         |  2 ++
>  src/gallium/drivers/nouveau/nv30/nv30_screen.c   |  2 ++
>  src/gallium/drivers/nouveau/nv50/nv50_screen.c   |  2 ++
>  src/gallium/drivers/nouveau/nvc0/nvc0_screen.c   |  2 ++
>  src/gallium/drivers/r300/r300_screen.c           |  2 ++
>  src/gallium/drivers/r600/r600_pipe.c             |  2 ++
>  src/gallium/drivers/radeonsi/si_pipe.c           |  2 ++
>  src/gallium/drivers/softpipe/sp_screen.c         |  2 ++
>  src/gallium/drivers/svga/svga_screen.c           |  2 ++
>  src/gallium/drivers/swr/swr_screen.cpp           |  2 ++
>  src/gallium/drivers/vc4/vc4_screen.c             |  2 ++
>  src/gallium/drivers/virgl/virgl_screen.c         |  2 ++
>  src/gallium/include/pipe/p_defines.h             |  3 +++
>  17 files changed, 45 insertions(+)
>