[Mesa-stable] [Mesa-dev] [PATCH 3/3] Revert "i965: Disable regular fast-clears (CCS_D) on gen9+"

Nanley Chery nanleychery at gmail.com
Sat Dec 16 22:35:24 UTC 2017


On Wed, Dec 13, 2017 at 05:52:03PM -0800, Jason Ekstrand wrote:
> This reverts commit ee57b15ec764736e2d5360beaef9fb2045ed0f68.
> 
> Cc: "17.3" <mesa-stable at lists.freedesktop.org>
> ---
>  src/mesa/drivers/dri/i965/brw_meta_util.c     | 10 -----
>  src/mesa/drivers/dri/i965/intel_mipmap_tree.c | 57 ++++++++++++---------------
>  2 files changed, 25 insertions(+), 42 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_meta_util.c b/src/mesa/drivers/dri/i965/brw_meta_util.c
> index 54dc6a5..b311815 100644
> --- a/src/mesa/drivers/dri/i965/brw_meta_util.c
> +++ b/src/mesa/drivers/dri/i965/brw_meta_util.c
> @@ -293,17 +293,7 @@ brw_is_color_fast_clear_compatible(struct brw_context *brw,
>         brw->mesa_to_isl_render_format[mt->format])
>        return false;
>  
> -   /* Gen9 doesn't support fast clear on single-sampled SRGB buffers. When
> -    * GL_FRAMEBUFFER_SRGB is enabled any color renderbuffers will be
> -    * resolved in intel_update_state. In that case it's pointless to do a
> -    * fast clear because it's very likely to be immediately resolved.
> -    */
>     const bool srgb_rb = _mesa_get_srgb_format_linear(mt->format) != mt->format;
> -   if (devinfo->gen >= 9 &&
> -       mt->surf.samples == 1 &&
> -       ctx->Color.sRGBEnabled && srgb_rb)
> -      return false;
> -
>    /* Gen10 doesn't automatically decode the clear color of sRGB buffers. Since
>     * we currently don't perform this decode in software, avoid a fast-clear
>     * altogether. TODO: Do this in software.
> diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> index c1a4ce1..b87d356 100644
> --- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> +++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> @@ -207,13 +207,7 @@ intel_miptree_supports_ccs(struct brw_context *brw,
>     if (!brw->mesa_format_supports_render[mt->format])
>        return false;
>  
> -   if (devinfo->gen >= 9) {
> -      mesa_format linear_format = _mesa_get_srgb_format_linear(mt->format);
> -      const enum isl_format isl_format =
> -         brw_isl_format_for_mesa_format(linear_format);
> -      return isl_format_supports_ccs_e(&brw->screen->devinfo, isl_format);
> -   } else
> -      return true;
> +   return true;
>  }
>  
>  static bool
> @@ -256,7 +250,7 @@ intel_miptree_supports_hiz(const struct brw_context *brw,
>   * our HW tends to support more linear formats than sRGB ones, we use this
>   * format variant for check for CCS_E compatibility.
>   */
> -MAYBE_UNUSED static bool
> +static bool
>  format_ccs_e_compat_with_miptree(const struct gen_device_info *devinfo,
>                                   const struct intel_mipmap_tree *mt,
>                                   enum isl_format access_format)
> @@ -290,12 +284,13 @@ intel_miptree_supports_ccs_e(struct brw_context *brw,
>     if (!intel_miptree_supports_ccs(brw, mt))
>        return false;
>  
> -   /* Fast clear can be also used to clear srgb surfaces by using equivalent
> -    * linear format. This trick, however, can't be extended to be used with
> -    * lossless compression and therefore a check is needed to see if the format
> -    * really is linear.
> +   /* Many window system buffers are sRGB even if they are never rendered as
> +    * sRGB.  For those, we want CCS_E for when sRGBEncode is false.  When the
> +    * surface is used as sRGB, we fall back to CCS_D.
>      */
> -   return _mesa_get_srgb_format_linear(mt->format) == mt->format;
> +   mesa_format linear_format = _mesa_get_srgb_format_linear(mt->format);
> +   enum isl_format isl_format = brw_isl_format_for_mesa_format(linear_format);
> +   return isl_format_supports_ccs_e(&brw->screen->devinfo, isl_format);
>  }
>  
>  /**
> @@ -2686,29 +2681,27 @@ intel_miptree_render_aux_usage(struct brw_context *brw,
>        return ISL_AUX_USAGE_MCS;
>  
>     case ISL_AUX_USAGE_CCS_D:
> -      /* If FRAMEBUFFER_SRGB is used on Gen9+ then we need to resolve any of
> -       * the single-sampled color renderbuffers because the CCS buffer isn't
> -       * supported for SRGB formats. This only matters if FRAMEBUFFER_SRGB is
> -       * enabled because otherwise the surface state will be programmed with
> -       * the linear equivalent format anyway.
> -       */
> -      if (isl_format_is_srgb(render_format) &&
> -          _mesa_get_srgb_format_linear(mt->format) != mt->format) {
> -         return ISL_AUX_USAGE_NONE;
> -      } else if (!mt->mcs_buf) {
> -         return ISL_AUX_USAGE_NONE;
> -      } else {
> -         return ISL_AUX_USAGE_CCS_D;
> -      }
> +      return mt->mcs_buf ? ISL_AUX_USAGE_CCS_D : ISL_AUX_USAGE_NONE;
>  
>     case ISL_AUX_USAGE_CCS_E: {
> -      /* Lossless compression is not supported for SRGB formats, it
> -       * should be impossible to get here with such surfaces.
> +      /* If the format supports CCS_E and is compatible with the miptree,
> +       * then we can use it.
>         */
> -      assert(!isl_format_is_srgb(render_format) ||
> -             _mesa_get_srgb_format_linear(mt->format) == mt->format);
> +      if (format_ccs_e_compat_with_miptree(&brw->screen->devinfo,
> +                                           mt, render_format))
> +         return ISL_AUX_USAGE_CCS_E;
> +
> +      /* Otherwise, we have to fall back to CCS_D */
> +
> +      /* gen9 hardware technically supports non-0/1 clear colors with sRGB
> +       * formats.  However, there are issues with blending where it doesn't
> +       * properly apply the sRGB curve to the clear color when blending.
> +       */
> +      if (blend_enabled && isl_format_is_srgb(render_format) &&
> +          !isl_color_value_is_zero_one(mt->fast_clear_color, render_format))
> +         return ISL_AUX_USAGE_NONE;
>  

We also need the blend workaround for the CCS_D case. Otherwise, we'll
start failing piglit's arb_framebuffer_srgb-fast-clear-blend when
DEBUG_NO_RBC is set (MD5-287).

-Nanley

> -      return ISL_AUX_USAGE_CCS_E;
> +      return ISL_AUX_USAGE_CCS_D;
>     }
>  
>     default:
> -- 
> 2.5.0.400.gff86faf
> 
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