[Mesa-dev] [PATCH 4/4] main: Use a derived value for the default sample count

[Ilia Mirkin]

On Thu, Feb 4, 2016 at 11:12 AM, Neil Roberts <neil at linux.intel.com> wrote:
> Previously the framebuffer default sample count was taken directly
> from the value given by the application. On the i965 driver on HSW if
> the value wasn't one that is supported by the hardware it would hit an
> assert when it tried to program the state for it. This patch fixes it
> by adding a derived sample count to the state for the default
> framebuffer. The driver can then quantize this to one of the valid
> values in its UpdateState handler when the _NEW_BUFFERS state changes.
> _mesa_geometric_samples is changed to use the new derived value.
>
> Fixes the piglit test arb_framebuffer_no_attachments-query
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93957
> Cc: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
>  src/mesa/drivers/dri/i965/brw_context.c | 19 +++++++++++++++++++
>  src/mesa/main/framebuffer.h             |  3 ++-
>  src/mesa/main/mtypes.h                  |  4 ++++
>  3 files changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
> index 1032e5a..44d2fe4 100644
> --- a/src/mesa/drivers/dri/i965/brw_context.c
> +++ b/src/mesa/drivers/dri/i965/brw_context.c
> @@ -167,6 +167,19 @@ intel_viewport(struct gl_context *ctx)
>  }
>
>  static void
> +intel_update_framebuffer(struct gl_context *ctx,
> +                         struct gl_framebuffer *fb)
> +{
> +   struct brw_context *brw = brw_context(ctx);
> +
> +   /* Quantize the derived default number of samples
> +    */

Not a lot of effort either way, but this only needs to be done if
!fb->_HasAttachments right?

> +   fb->DefaultGeometry._NumSamples =
> +      intel_quantize_num_samples(brw->intelScreen,
> +                                 fb->DefaultGeometry.NumSamples);
> +}
> +
> +static void
>  intel_update_state(struct gl_context * ctx, GLuint new_state)
>  {
>     struct brw_context *brw = brw_context(ctx);
> @@ -245,6 +258,12 @@ intel_update_state(struct gl_context * ctx, GLuint new_state)
>     }
>
>     _mesa_lock_context_textures(ctx);
> +
> +   if (new_state & _NEW_BUFFERS) {
> +      intel_update_framebuffer(ctx, ctx->DrawBuffer);
> +      if (ctx->DrawBuffer != ctx->ReadBuffer)
> +         intel_update_framebuffer(ctx, ctx->ReadBuffer);
> +   }
>  }
>
>  #define flushFront(screen)      ((screen)->image.loader ? (screen)->image.loader->flushFrontBuffer : (screen)->dri2.loader->flushFrontBuffer)
> diff --git a/src/mesa/main/framebuffer.h b/src/mesa/main/framebuffer.h
> index ab077ed..fa434d4 100644
> --- a/src/mesa/main/framebuffer.h
> +++ b/src/mesa/main/framebuffer.h
> @@ -97,7 +97,8 @@ static inline GLuint
>  _mesa_geometric_samples(const struct gl_framebuffer *buffer)
>  {
>     return buffer->_HasAttachments ?
> -      buffer->Visual.samples : buffer->DefaultGeometry.NumSamples;
> +      buffer->Visual.samples :
> +      buffer->DefaultGeometry._NumSamples;
>  }
>
>  static inline GLuint
> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> index 58064aa..745eeb8 100644
> --- a/src/mesa/main/mtypes.h
> +++ b/src/mesa/main/mtypes.h
> @@ -3223,6 +3223,10 @@ struct gl_framebuffer
>     struct {
>       GLuint Width, Height, Layers, NumSamples;
>       GLboolean FixedSampleLocations;
> +     /* Derived from NumSamples by the driver so that it can choose a valid
> +      * value for the hardware.
> +      */
> +     GLuint _NumSamples;
>     } DefaultGeometry;
>
>     /** \name  Drawing bounds (Intersection of buffer size and scissor box)
> --
> 2.5.0
>