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

Chad Versace chadversary at chromium.org
Fri May 12 03:42:47 UTC 2017


On Thu 11 May 2017, Pohjolainen, Topi wrote:
> 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>

Me too. Combining the two functions really simplifies things.
Reviewed-by: Chad Versace <chadversary at chromium.org>

Please fix the hiccup in the commit message ("we then to").


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