[Mesa-dev] [PATCH 2/4] intel/isl: Refactor gen7_choose_image_alignment_el

Pohjolainen, Topi topi.pohjolainen at gmail.com
Thu May 11 13:54:50 UTC 2017


On Wed, May 10, 2017 at 02:30:30PM -0700, Jason Ekstrand wrote:
> The Ivy Bridge PRM provides a nice table that handles most of the
> alignment cases in one place.  For standard color buffers we have a
> little freedom of choice but for most depth, stencil and compressed it's
> hard-coded.  Chad's original functions split halign and valign apart and
> implemented them almost entirely based on restrictions and not the
> table.  This makes things way more confusing than they need to be.  This
> commit gets rid of the split and makes us implement the exact table
> up-front.  If our surface isn't one of the ones in the table we then to
> on to make real choices.
> ---
>  src/intel/isl/isl_gen7.c | 161 +++++++++++++++++++++++------------------------
>  1 file changed, 78 insertions(+), 83 deletions(-)
> 
> diff --git a/src/intel/isl/isl_gen7.c b/src/intel/isl/isl_gen7.c
> index 8e6b441..4c8f530 100644
> --- a/src/intel/isl/isl_gen7.c
> +++ b/src/intel/isl/isl_gen7.c
> @@ -289,105 +289,100 @@ isl_gen6_filter_tiling(const struct isl_device *dev,
>        *flags &= ~ISL_TILING_Y0_BIT;
>  }
>  
> -/**
> - * Choose horizontal subimage alignment, in units of surface elements.
> - */
> -static uint32_t
> -gen7_choose_halign_el(const struct isl_device *dev,
> -                      const struct isl_surf_init_info *restrict info)
> +void
> +isl_gen7_choose_image_alignment_el(const struct isl_device *dev,
> +                                   const struct isl_surf_init_info *restrict info,
> +                                   enum isl_tiling tiling,
> +                                   enum isl_dim_layout dim_layout,
> +                                   enum isl_msaa_layout msaa_layout,
> +                                   struct isl_extent3d *image_align_el)
>  {
> -   if (isl_format_is_compressed(info->format))
> -      return 1;
> +   assert(ISL_DEV_GEN(dev) == 7);
>  
> -   /* From the Ivybridge PRM (2012-05-31), Volume 4, Part 1, Section 2.12.1,
> -    * RENDER_SURFACE_STATE Surface Hoizontal Alignment:
> +   /* Handled by isl_choose_image_alignment_el */
> +   assert(info->format != ISL_FORMAT_HIZ);
> +
> +   /* IVB+ does not support combined depthstencil. */
> +   assert(!isl_surf_usage_is_depth_and_stencil(info->usage));
> +
> +   /* From the Ivy Bridge PRM, Vol. 2, Part 2, Section 6.18.4.4,
> +    * "Alignment unit size", the alignment parameters are summarized in the
> +    * following table:
>      *
> -    *    - This field is intended to be set to HALIGN_8 only if the surface
> -    *      was rendered as a depth buffer with Z16 format or a stencil buffer,
> -    *      since these surfaces support only alignment of 8. Use of HALIGN_8
> -    *      for other surfaces is supported, but uses more memory.
> +    *     Surface Defined By | Surface Format  | Align Width | Align Height
> +    *    --------------------+-----------------+-------------+--------------
> +    *       DEPTH_BUFFER     |   D16_UNORM     |      8      |      4
> +    *                        |     other       |      4      |      4
> +    *    --------------------+-----------------+-------------+--------------
> +    *       STENCIL_BUFFER   |      N/A        |      8      |      8
> +    *    --------------------+-----------------+-------------+--------------
> +    *       SURFACE_STATE    | BC*, ETC*, EAC* |      4      |      4
> +    *                        |      FXT1       |      8      |      4
> +    *                        |   all others    |   HALIGN    |   VALIGN
> +    *    -------------------------------------------------------------------
>      */
> -   if (isl_surf_info_is_z16(info) ||
> -       isl_surf_usage_is_stencil(info->usage))
> -      return 8;
> -
> -   return 4;
> -}
> +   if (isl_surf_usage_is_depth(info->usage)) {
> +      if (info->format == ISL_FORMAT_R16_UNORM) {
> +         *image_align_el = isl_extent3d(8, 4, 1);
> +         return;
> +      } else {
> +         *image_align_el = isl_extent3d(4, 4, 1);
> +         return;
> +      }
> +   } else if (isl_surf_usage_is_stencil(info->usage)) {
> +      *image_align_el = isl_extent3d(8, 8, 1);
> +      return;
> +   } else if (isl_format_is_compressed(info->format)) {
> +      /* Compressed formats all have alignment equal to block size. */
> +      *image_align_el = isl_extent3d(1, 1, 1);
> +      return;
> +   }
>  
> -/**
> - * Choose vertical subimage alignment, in units of surface elements.
> - */
> -static uint32_t
> -gen7_choose_valign_el(const struct isl_device *dev,
> -                      const struct isl_surf_init_info *restrict info,
> -                      enum isl_tiling tiling)
> -{
> -   MAYBE_UNUSED bool require_valign2 = false;
> -   bool require_valign4 = false;
> +   /* Everything after this point is in the "set by Surface Horizontal or
> +    * Vertical Alignment" case.  Now it's just a matter of applying
> +    * restrictions.
> +    */
>  
> -   if (isl_format_is_compressed(info->format))
> -      return 1;
> +   /* There are no restrictions on halign beyond what's given in the table
> +    * above.  We set it to the minimum value of 4 because that uses the least
> +    * memory.
> +    */
> +   const uint32_t halign = 4;
>  
> -   if (gen7_format_needs_valign2(dev, info->format))
> -      require_valign2 = true;
> +   bool require_valign4 = false;
>  
>     /* From the Ivybridge PRM, Volume 4, Part 1, Section 2.12.1:
>      * RENDER_SURFACE_STATE Surface Vertical Alignment:
>      *
> -    *    - This field is intended to be set to VALIGN_4 if the surface was
> -    *      rendered as a depth buffer, for a multisampled (4x) render target,
> -    *      or for a multisampled (8x) render target, since these surfaces
> -    *      support only alignment of 4.  Use of VALIGN_4 for other surfaces is
> -    *      supported, but uses more memory.  This field must be set to
> -    *      VALIGN_4 for all tiled Y Render Target surfaces.
> +    *    * This field is intended to be set to VALIGN_4 if the surface was
> +    *      rendered as a depth buffer,
>      *
> +    *    * for a multisampled (4x) render target, or for a multisampled (8x)
> +    *      render target, since these surfaces support only alignment of 4.
> +    *
> +    *    * This field must be set to VALIGN_4 for all tiled Y Render Target
> +    *      surfaces
> +    *
> +    *    * Value of 1 is not supported for format YCRCB_NORMAL (0x182),
> +    *      YCRCB_SWAPUVY (0x183), YCRCB_SWAPUV (0x18f), YCRCB_SWAPY (0x190)
> +    *
> +    *    * If Number of Multisamples is not MULTISAMPLECOUNT_1, this field
> +    *      must be set to VALIGN_4."
> +    *
> +    * The first restriction is already handled by the table above and the
> +    * second restriction is redundant with the fifth.
>      */
> -   if (isl_surf_usage_is_depth(info->usage) ||
> -       info->samples > 1 ||
> -       ((info->usage & ISL_SURF_USAGE_RENDER_TARGET_BIT) &&
> -        tiling == ISL_TILING_Y0)) {
> +   if (info->samples > 1)
>        require_valign4 = true;
> -   }
> -
> -   if (isl_surf_usage_is_stencil(info->usage)) {
> -      /* The Ivybridge PRM states that the stencil buffer's vertical alignment
> -       * is 8 [Ivybridge PRM, Volume 1, Part 1, Section 6.18.4.4 Alignment
> -       * Unit Size]. valign=8 is outside the set of valid values of
> -       * RENDER_SURFACE_STATE.SurfaceVerticalAlignment, but that's ok because
> -       * a stencil buffer will never be used directly for texturing or
> -       * rendering on gen7.
> -       */
> -      return 8;
> -   }
> -
> -   assert(!require_valign2 || !require_valign4);
> -
> -   if (require_valign4)
> -      return 4;
>  
> -   /* Prefer VALIGN_2 because it conserves memory. */
> -   return 2;
> -}
> -
> -void
> -isl_gen7_choose_image_alignment_el(const struct isl_device *dev,
> -                                   const struct isl_surf_init_info *restrict info,
> -                                   enum isl_tiling tiling,
> -                                   enum isl_dim_layout dim_layout,
> -                                   enum isl_msaa_layout msaa_layout,
> -                                   struct isl_extent3d *image_align_el)
> -{
> -   assert(ISL_DEV_GEN(dev) == 7);
> +   if (tiling == ISL_TILING_Y0 &&
> +       (info->usage & ISL_SURF_USAGE_RENDER_TARGET_BIT))
> +      require_valign4 = true;
>  
> -   /* Handled by isl_choose_image_alignment_el */
> -   assert(info->format != ISL_FORMAT_HIZ);
> +   assert(!(require_valign4 && gen7_format_needs_valign2(dev, info->format)));
>  
> -   /* IVB+ does not support combined depthstencil. */
> -   assert(!isl_surf_usage_is_depth_and_stencil(info->usage));
> +   /* We default to HALIGN_2 because it uses the least memory. */

                       VALIGN_2

Otherwise looks good to me:

Reviewed-by: Topi Pohjolainen <topi.pohjolainen at intel.com>

> +   const uint32_t valign = require_valign4 ? 4 : 2;
>  
> -   *image_align_el = (struct isl_extent3d) {
> -      .w = gen7_choose_halign_el(dev, info),
> -      .h = gen7_choose_valign_el(dev, info, tiling),
> -      .d = 1,
> -   };
> +   *image_align_el = isl_extent3d(halign, valign, 1);
>  }
> -- 
> 2.5.0.400.gff86faf
> 
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