[Mesa-dev] [PATCH 2/6] r600g: Add r600_rat_buffer_create()

Marek Olšák maraeo at gmail.com
Fri Sep 21 20:31:51 PDT 2012


Hi Tom,

First I'd like to say that even though I don't agree with the
direction you're taking, I'd be okay with it for initial bring-up of
the compute support.

I am not in favor of using radeon_surface for plain untyped 1D
buffers, where the only thing that really matters is the buffer
alignment, right? I am also curious about what is so special about
radeon_surface that we need to use it to allocate the RAT buffers.

The other issue is that this solution doesn't scale. It would be
impossible to use an ordinary buffer created using resource_create as
a RAT. Does the hardware really impose special restrictions on RATs
such that the the current buffer allocation codepath cannot be used?
Would such a restriction disallow interoperability with GL or even
disallow implementing GL_ARB_shader_storage_buffer_object? That
extension allows reads from and writes to ordinary GL buffers in all
shader stages (though only the fragment and compute shader support is
mandatory) and, of course, the buffers can be later used as a source
for vertices, indices, uniforms, etc, and vice versa, any buffer can
be used as a "shader storage buffer object".

Now some comments about the code...

I don't like allocating r600_texture for PIPE_BUFFER. The problem is
if you got a pipe_resource, there would be no way to tell if it's
actually r600_texture or r600_resource. If using radeon_surface is the
way to go, let's move radeon_surface into r600_resource.

Also checking for R600_RESOURCE_FLAG_FLUSHED_DEPTH doesn't seem to be
very useful there (it's not an allocation of a depth-stencil texture).

Marek

On Fri, Sep 21, 2012 at 10:39 PM, Tom Stellard <tom at stellard.net> wrote:
> From: Tom Stellard <thomas.stellard at amd.com>
>
> This function creates a buffer with an associated radeon_surface that
> can be used as a RAT.
> ---
>  src/gallium/drivers/r600/r600_buffer.c   | 69 ++++++++++++++++++++++++++++----
>  src/gallium/drivers/r600/r600_pipe.h     |  2 +
>  src/gallium/drivers/r600/r600_resource.h |  5 +++
>  src/gallium/drivers/r600/r600_texture.c  |  2 +-
>  4 files changed, 69 insertions(+), 9 deletions(-)
>
> diff --git a/src/gallium/drivers/r600/r600_buffer.c b/src/gallium/drivers/r600/r600_buffer.c
> index 0b0ac34..5bc3d72 100644
> --- a/src/gallium/drivers/r600/r600_buffer.c
> +++ b/src/gallium/drivers/r600/r600_buffer.c
> @@ -24,6 +24,7 @@
>   *      Jerome Glisse
>   *      Corbin Simpson <MostAwesomeDude at gmail.com>
>   */
> +#include "r600d.h"
>  #include "r600_pipe.h"
>  #include "util/u_upload_mgr.h"
>  #include "util/u_memory.h"
> @@ -239,6 +240,65 @@ bool r600_init_resource(struct r600_screen *rscreen,
>         return true;
>  }
>
> +static int r600_buffer_init(struct r600_resource *rbuffer,
> +                       struct r600_screen *rscreen,
> +                       const struct pipe_resource *templ,
> +                       unsigned alignment)
> +
> +{
> +       rbuffer->b.b = *templ;
> +       pipe_reference_init(&rbuffer->b.b.reference, 1);
> +       rbuffer->b.b.screen = (struct pipe_screen *)rscreen;
> +       rbuffer->b.vtbl = &r600_buffer_vtbl;
> +
> +       if (!r600_init_resource(rscreen, rbuffer, templ->width0, alignment, templ->bind, templ->usage)) {
> +               FREE(rbuffer);
> +               return -1;
> +       }
> +       return 0;
> +}
> +
> +/**
> + * Create a buffer that can be used as a RAT and also passed to
> + * evergreen_init_color surface.
> + */
> +struct r600_texture *r600_rat_buffer_create(struct pipe_screen *screen,
> +                                       const struct pipe_resource *templ)
> +{
> +       struct r600_screen *rscreen = (struct r600_screen*)screen;
> +       struct r600_texture *rtex;
> +       int r;
> +
> +       rtex = CALLOC_STRUCT(r600_texture);
> +       if (!rtex)
> +               goto fail;
> +
> +       r = r600_init_surface(rscreen, &rtex->surface, templ,
> +                       V_038000_ARRAY_LINEAR_ALIGNED,
> +                       templ->flags & R600_RESOURCE_FLAG_TRANSFER,
> +                       templ->flags & R600_RESOURCE_FLAG_FLUSHED_DEPTH);
> +       if (r)
> +               goto fail;
> +
> +       r = rscreen->ws->surface_best(rscreen->ws, &rtex->surface);
> +
> +       if (r)
> +               goto fail;
> +
> +       rtex->is_rat = 1;
> +
> +       r = r600_buffer_init(&rtex->resource, rscreen, templ,
> +                       rtex->surface.bo_alignment);
> +       if (r)
> +               goto fail;
> +
> +       return rtex;
> +
> +fail:
> +       FREE(rtex);
> +       return NULL;
> +}
> +
>  struct pipe_resource *r600_buffer_create(struct pipe_screen *screen,
>                                          const struct pipe_resource *templ,
>                                          unsigned alignment)
> @@ -248,14 +308,7 @@ struct pipe_resource *r600_buffer_create(struct pipe_screen *screen,
>
>         rbuffer = MALLOC_STRUCT(r600_resource);
>
> -       rbuffer->b.b = *templ;
> -       pipe_reference_init(&rbuffer->b.b.reference, 1);
> -       rbuffer->b.b.screen = screen;
> -       rbuffer->b.vtbl = &r600_buffer_vtbl;
> +       r600_buffer_init(rbuffer, rscreen, templ, alignment);
>
> -       if (!r600_init_resource(rscreen, rbuffer, templ->width0, alignment, templ->bind, templ->usage)) {
> -               FREE(rbuffer);
> -               return NULL;
> -       }
>         return &rbuffer->b.b;
>  }
> diff --git a/src/gallium/drivers/r600/r600_pipe.h b/src/gallium/drivers/r600/r600_pipe.h
> index 1428e9a..80ac5d0 100644
> --- a/src/gallium/drivers/r600/r600_pipe.h
> +++ b/src/gallium/drivers/r600/r600_pipe.h
> @@ -552,6 +552,8 @@ bool r600_init_resource(struct r600_screen *rscreen,
>  struct pipe_resource *r600_buffer_create(struct pipe_screen *screen,
>                                          const struct pipe_resource *templ,
>                                          unsigned alignment);
> +struct r600_texture *r600_rat_buffer_create(struct pipe_screen *screen,
> +                                       const struct pipe_resource *templ);
>
>  /* r600_pipe.c */
>  void r600_flush(struct pipe_context *ctx, struct pipe_fence_handle **fence,
> diff --git a/src/gallium/drivers/r600/r600_resource.h b/src/gallium/drivers/r600/r600_resource.h
> index a5a5404..28a72b0 100644
> --- a/src/gallium/drivers/r600/r600_resource.h
> +++ b/src/gallium/drivers/r600/r600_resource.h
> @@ -125,6 +125,11 @@ void r600_texture_get_fmask_info(struct r600_screen *rscreen,
>  void r600_texture_get_cmask_info(struct r600_screen *rscreen,
>                                  struct r600_texture *rtex,
>                                  struct r600_cmask_info *out);
> +int r600_init_surface(struct r600_screen *rscreen,
> +                            struct radeon_surface *surface,
> +                            const struct pipe_resource *ptex,
> +                            unsigned array_mode,
> +                            bool is_transfer, bool is_flushed_depth);
>  struct pipe_resource *r600_texture_create(struct pipe_screen *screen,
>                                         const struct pipe_resource *templ);
>  struct pipe_resource *r600_texture_from_handle(struct pipe_screen *screen,
> diff --git a/src/gallium/drivers/r600/r600_texture.c b/src/gallium/drivers/r600/r600_texture.c
> index 7dc3fa5..58bfa54 100644
> --- a/src/gallium/drivers/r600/r600_texture.c
> +++ b/src/gallium/drivers/r600/r600_texture.c
> @@ -65,7 +65,7 @@ unsigned r600_texture_get_offset(struct r600_texture *rtex,
>                layer * rtex->surface.level[level].slice_size;
>  }
>
> -static int r600_init_surface(struct r600_screen *rscreen,
> +int r600_init_surface(struct r600_screen *rscreen,
>                              struct radeon_surface *surface,
>                              const struct pipe_resource *ptex,
>                              unsigned array_mode,
> --
> 1.7.11.4
>
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