[Mesa-dev] [PATCH 11/15] i965/msaa: Properly handle sliced layout for Gen7.

Paul Berry stereotype441 at gmail.com
Wed May 23 08:01:45 PDT 2012


On 22 May 2012 09:21, Paul Berry <stereotype441 at gmail.com> wrote:

> On 22 May 2012 08:19, Kenneth Graunke <kenneth at whitecape.org> wrote:
>
>> On 05/11/2012 11:03 AM, Paul Berry wrote:
>>
>>> Starting in Gen7, there are two possible layouts for MSAA surfaces:
>>>
>>> - Interleaved, in which additional samples are accommodated by scaling
>>>   up the width and height of the surface.  This is the only layout
>>>   available in Gen6.  On Gen7 it is used for depth and stencil
>>>   surfaces only.
>>>
>>> - Sliced, in which the surface is stored as a 2D array, with array
>>>   slice n containing all pixel data for sample n.  On Gen7 this layout
>>>   is used for color surfaces.
>>>
>>> The "Sliced" layout has an additional requirement: it must be used in
>>> ARYSPC_LOD0 mode, which means that the surface doesn't leave any extra
>>> room between array slices for miplevels other than 0.
>>>
>>> This patch modifies the surface allocation functions to use the
>>> correct layout when allocating MSAA surfaces in Gen7, and to set the
>>> array offsets properly when using ARYSPC_LOD0 mode.  It also modifies
>>> the code that populates SURFACE_STATE structures to ensure that
>>> ARYSPC_LOD0 mode is selected in the appropriate circumstances.
>>> ---
>>>  src/mesa/drivers/dri/i965/brw_**blorp.cpp           |    1 +
>>>  src/mesa/drivers/dri/i965/brw_**blorp.h             |    5 +
>>>  src/mesa/drivers/dri/i965/brw_**tex_layout.c        |   10 ++-
>>>  src/mesa/drivers/dri/i965/brw_**wm_surface_state.c  |    3 +-
>>>  src/mesa/drivers/dri/i965/**gen7_blorp.cpp          |    2 +
>>>  src/mesa/drivers/dri/i965/**gen7_wm_surface_state.c |   10 ++
>>>  src/mesa/drivers/dri/intel/**intel_mipmap_tree.c    |  102
>>> ++++++++++++++++-----
>>>  src/mesa/drivers/dri/intel/**intel_mipmap_tree.h    |   23 +++++-
>>>  src/mesa/drivers/dri/intel/**intel_tex_image.c      |    3 +-
>>>  src/mesa/drivers/dri/intel/**intel_tex_validate.c   |    3 +-
>>>  10 files changed, 134 insertions(+), 28 deletions(-)
>>>
>>> diff --git a/src/mesa/drivers/dri/i965/**brw_blorp.cpp
>>> b/src/mesa/drivers/dri/i965/**brw_blorp.cpp
>>> index f6aff44..84f92b4 100644
>>> --- a/src/mesa/drivers/dri/i965/**brw_blorp.cpp
>>> +++ b/src/mesa/drivers/dri/i965/**brw_blorp.cpp
>>> @@ -58,6 +58,7 @@ brw_blorp_surface_info::set(**struct
>>> intel_mipmap_tree *mt,
>>>  {
>>>     brw_blorp_mip_info::set(mt, level, layer);
>>>     this->num_samples = mt->num_samples;
>>> +   this->array_spacing_lod0 = mt->array_spacing_lod0;
>>>
>>>     if (mt->format == MESA_FORMAT_S8) {
>>>        /* The miptree is a W-tiled stencil buffer.  Surface states can't
>>> be set
>>> diff --git a/src/mesa/drivers/dri/i965/**brw_blorp.h
>>> b/src/mesa/drivers/dri/i965/**brw_blorp.h
>>> index 8dabf2c..3e37081 100644
>>> --- a/src/mesa/drivers/dri/i965/**brw_blorp.h
>>> +++ b/src/mesa/drivers/dri/i965/**brw_blorp.h
>>> @@ -99,6 +99,11 @@ public:
>>>     bool map_stencil_as_y_tiled;
>>>
>>>     unsigned num_samples;
>>> +
>>> +   /* Setting this flag indicates that the surface should be set up in
>>> +    * ARYSPC_LOD0 mode.  Ignored prior to Gen7.
>>> +    */
>>> +   bool array_spacing_lod0;
>>>  };
>>>
>>>
>>> diff --git a/src/mesa/drivers/dri/i965/**brw_tex_layout.c
>>> b/src/mesa/drivers/dri/i965/**brw_tex_layout.c
>>> index 8bf1d3d..f742131 100644
>>> --- a/src/mesa/drivers/dri/i965/**brw_tex_layout.c
>>> +++ b/src/mesa/drivers/dri/i965/**brw_tex_layout.c
>>> @@ -49,7 +49,10 @@ brw_miptree_layout_texture_**array(struct
>>> intel_context *intel,
>>>
>>>     h0 = ALIGN(mt->height0, mt->align_h);
>>>     h1 = ALIGN(minify(mt->height0), mt->align_h);
>>> -   qpitch = (h0 + h1 + (intel->gen>= 7 ? 12 : 11) * mt->align_h);
>>> +   if (mt->array_spacing_lod0)
>>> +      qpitch = h0;
>>> +   else
>>> +      qpitch = (h0 + h1 + (intel->gen>= 7 ? 12 : 11) * mt->align_h);
>>>     if (mt->compressed)
>>>        qpitch /= 4;
>>>
>>> @@ -165,7 +168,10 @@ brw_miptree_layout(struct intel_context *intel,
>>> struct intel_mipmap_tree *mt)
>>>        break;
>>>
>>>     default:
>>> -      i945_miptree_layout_2d(mt);
>>> +      if (mt->num_samples>  0&&  !mt->msaa_is_interleaved)
>>>
>>> +         brw_miptree_layout_texture_**array(intel, mt);
>>> +      else
>>> +         i945_miptree_layout_2d(mt);
>>>        break;
>>>     }
>>>     DBG("%s: %dx%dx%d\n", __FUNCTION__,
>>> diff --git a/src/mesa/drivers/dri/i965/**brw_wm_surface_state.c
>>> b/src/mesa/drivers/dri/i965/**brw_wm_surface_state.c
>>> index 849da85..6e745cf 100644
>>> --- a/src/mesa/drivers/dri/i965/**brw_wm_surface_state.c
>>> +++ b/src/mesa/drivers/dri/i965/**brw_wm_surface_state.c
>>> @@ -955,7 +955,8 @@ brw_update_renderbuffer_**surface(struct
>>> brw_context *brw,
>>>                                       intel_image->base.Base.Level,
>>>                                       width, height, depth,
>>>                                       true,
>>> -                                       0 /* num_samples */);
>>> +                                       0 /* num_samples */,
>>> +                                       false /* msaa_is_interleaved */);
>>>
>>>         intel_miptree_copy_teximage(**intel, intel_image, new_mt);
>>>         intel_miptree_reference(&irb->**mt, intel_image->mt);
>>> diff --git a/src/mesa/drivers/dri/i965/**gen7_blorp.cpp
>>> b/src/mesa/drivers/dri/i965/**gen7_blorp.cpp
>>> index 3775eec..dfc2272 100644
>>> --- a/src/mesa/drivers/dri/i965/**gen7_blorp.cpp
>>> +++ b/src/mesa/drivers/dri/i965/**gen7_blorp.cpp
>>> @@ -149,6 +149,8 @@ gen7_blorp_emit_surface_state(**struct brw_context
>>> *brw,
>>>
>>>     surf->ss0.surface_format = format;
>>>     surf->ss0.surface_type = BRW_SURFACE_2D;
>>> +   surf->ss0.surface_array_**spacing = surface->array_spacing_lod0 ?
>>> +      GEN7_SURFACE_ARYSPC_LOD0 : GEN7_SURFACE_ARYSPC_FULL;
>>>
>>>     /* reloc */
>>>     surf->ss1.base_addr = region->bo->offset; /* No tile offsets needed
>>> */
>>> diff --git a/src/mesa/drivers/dri/i965/**gen7_wm_surface_state.c
>>> b/src/mesa/drivers/dri/i965/**gen7_wm_surface_state.c
>>> index 5aa62bd..9a01ddf 100644
>>> --- a/src/mesa/drivers/dri/i965/**gen7_wm_surface_state.c
>>> +++ b/src/mesa/drivers/dri/i965/**gen7_wm_surface_state.c
>>> @@ -142,6 +142,10 @@ gen7_update_texture_surface(**struct gl_context
>>> *ctx, GLuint unit)
>>>        return;
>>>     }
>>>
>>> +   /* We don't support MSAA for textures. */
>>> +   assert(!mt->array_spacing_**lod0);
>>> +   assert(mt->num_samples == 0);
>>> +
>>>     intel_miptree_get_dimensions_**for_image(firstImage,&width,&**
>>> height,&depth);
>>>
>>>     surf = brw_state_batch(brw, AUB_TRACE_SURFACE_STATE,
>>> @@ -296,6 +300,9 @@ gen7_update_renderbuffer_**surface(struct
>>> brw_context *brw,
>>>                          sizeof(*surf), 32,&brw->wm.surf_offset[unit])**
>>> ;
>>>
>>>     memset(surf, 0, sizeof(*surf));
>>>
>>> +   /* Render targets can't use MSAA interleaved layout */
>>> +   assert(!irb->mt->msaa_is_**interleaved);
>>> +
>>>     if (irb->mt->align_h == 4)
>>>        surf->ss0.vertical_alignment = 1;
>>>     if (irb->mt->align_w == 8)
>>> @@ -324,6 +331,9 @@ gen7_update_renderbuffer_**surface(struct
>>> brw_context *brw,
>>>     }
>>>
>>>     surf->ss0.surface_type = BRW_SURFACE_2D;
>>> +   surf->ss0.surface_array_**spacing = irb->mt->array_spacing_lod0 ?
>>> +      GEN7_SURFACE_ARYSPC_LOD0 : GEN7_SURFACE_ARYSPC_FULL;
>>> +
>>>     /* reloc */
>>>     surf->ss1.base_addr = intel_renderbuffer_tile_**
>>> offsets(irb,&tile_x,&tile_y);
>>>     surf->ss1.base_addr += region->bo->offset; /* reloc */
>>> diff --git a/src/mesa/drivers/dri/intel/**intel_mipmap_tree.c
>>> b/src/mesa/drivers/dri/intel/**intel_mipmap_tree.c
>>> index 36d7b77..4132351 100644
>>> --- a/src/mesa/drivers/dri/intel/**intel_mipmap_tree.c
>>> +++ b/src/mesa/drivers/dri/intel/**intel_mipmap_tree.c
>>> @@ -73,7 +73,8 @@ intel_miptree_create_internal(**struct intel_context
>>> *intel,
>>>                              GLuint height0,
>>>                              GLuint depth0,
>>>                              bool for_region,
>>> -                              GLuint num_samples)
>>> +                              GLuint num_samples,
>>> +                              bool msaa_is_interleaved)
>>>  {
>>>     struct intel_mipmap_tree *mt = calloc(sizeof(*mt), 1);
>>>     int compress_byte = 0;
>>> @@ -95,8 +96,14 @@ intel_miptree_create_internal(**struct intel_context
>>> *intel,
>>>     mt->cpp = compress_byte ? compress_byte : _mesa_get_format_bytes(mt->
>>> **format);
>>>     mt->num_samples = num_samples;
>>>     mt->compressed = compress_byte ? 1 : 0;
>>> +   mt->msaa_is_interleaved = msaa_is_interleaved;
>>>     mt->refcount = 1;
>>>
>>> +   /* array_spacing_lod0 is only used for non-interleaved MSAA surfaces.
>>> +    * TODO: can we use it elsewhere?
>>> +    */
>>> +   mt->array_spacing_lod0 = num_samples>  0&&  !msaa_is_interleaved;
>>>
>>> +
>>>     if (target == GL_TEXTURE_CUBE_MAP) {
>>>        assert(depth0 == 1);
>>>        mt->depth0 = 6;
>>> @@ -109,6 +116,8 @@ intel_miptree_create_internal(**struct
>>> intel_context *intel,
>>>         (intel->must_use_separate_**stencil ||
>>>        (intel->has_separate_stencil&&
>>>        intel->vtbl.is_hiz_depth_**format(intel, format)))) {
>>> +      /* MSAA stencil surfaces are always interleaved. */
>>> +      bool msaa_is_interleaved = num_samples>  0;
>>>        mt->stencil_mt = intel_miptree_create(intel,
>>>                                              mt->target,
>>>                                              MESA_FORMAT_S8,
>>> @@ -118,7 +127,8 @@ intel_miptree_create_internal(**struct
>>> intel_context *intel,
>>>                                              mt->height0,
>>>                                              mt->depth0,
>>>                                              true,
>>> -                                            num_samples);
>>> +                                            num_samples,
>>> +                                            msaa_is_interleaved);
>>>        if (!mt->stencil_mt) {
>>>         intel_miptree_release(&mt);
>>>         return NULL;
>>> @@ -165,7 +175,8 @@ intel_miptree_create(struct intel_context *intel,
>>>                     GLuint height0,
>>>                     GLuint depth0,
>>>                     bool expect_accelerated_upload,
>>> -                     GLuint num_samples)
>>> +                     GLuint num_samples,
>>> +                     bool msaa_is_interleaved)
>>>  {
>>>     struct intel_mipmap_tree *mt;
>>>     uint32_t tiling = I915_TILING_NONE;
>>> @@ -207,7 +218,7 @@ intel_miptree_create(struct intel_context *intel,
>>>     mt = intel_miptree_create_internal(**intel, target, format,
>>>                                      first_level, last_level, width0,
>>>                                      height0, depth0,
>>> -                                     false, num_samples);
>>> +                                     false, num_samples,
>>> msaa_is_interleaved);
>>>     /*
>>>      * pitch == 0 || height == 0  indicates the null texture
>>>      */
>>> @@ -243,7 +254,8 @@ intel_miptree_create_for_**region(struct
>>> intel_context *intel,
>>>     mt = intel_miptree_create_internal(**intel, target, format,
>>>                                      0, 0,
>>>                                      region->width, region->height, 1,
>>> -                                     true, 0 /* num_samples */);
>>> +                                     true, 0 /* num_samples */,
>>> +                                      false /* msaa_is_interleaved */);
>>>     if (!mt)
>>>        return mt;
>>>
>>> @@ -252,6 +264,31 @@ intel_miptree_create_for_**region(struct
>>> intel_context *intel,
>>>     return mt;
>>>  }
>>>
>>> +/**
>>> + * Determine whether the MSAA surface being created should use an
>>> interleaved
>>> + * layout or a sliced layout, based on the chip generation and the
>>> surface
>>> + * type.
>>> + */
>>> +static bool
>>> +msaa_format_is_interleaved(**struct intel_context *intel, gl_format
>>> format)
>>> +{
>>> +   /* Prior to Gen7, all surfaces used interleaved layout. */
>>> +   if (intel->gen<  7)
>>> +      return true;
>>> +
>>> +   /* In Gen7, interleaved layout is only used for depth and stencil
>>> +    * buffers.
>>> +    */
>>> +   switch (_mesa_get_format_base_format(**format)) {
>>> +   case GL_DEPTH_COMPONENT:
>>> +   case GL_STENCIL_INDEX:
>>> +   case GL_DEPTH_STENCIL:
>>> +      return true;
>>> +   default:
>>> +      return false;
>>> +   }
>>> +}
>>> +
>>>  struct intel_mipmap_tree*
>>>  intel_miptree_create_for_**renderbuffer(struct intel_context *intel,
>>>                                        gl_format format,
>>> @@ -260,25 +297,43 @@ intel_miptree_create_for_**renderbuffer(struct
>>> intel_context *intel,
>>>                                        uint32_t num_samples)
>>>  {
>>>     struct intel_mipmap_tree *mt;
>>> -
>>> -   /* Adjust width/height for MSAA.  Note: since samples are
>>> interleaved in a
>>> -    * complex pattern that repeats for every 2x2 block of pixels, we
>>> need to
>>> -    * expand the width and height to even numbers before the
>>> width/height
>>> -    * adjustment, otherwise some of the samples in the last row and
>>> column
>>> -    * will fall outside the boundary of the texture.
>>> -    */
>>> -   if (num_samples>  4) {
>>> -      num_samples = 8;
>>> -      width = ALIGN(width, 2) * 4;
>>> -      height = ALIGN(height, 2) * 2;
>>> -   } else if (num_samples>  0) {
>>> -      num_samples = 4;
>>> -      width = ALIGN(width, 2) * 2;
>>> -      height = ALIGN(height, 2) * 2;
>>> +   uint32_t depth = 1;
>>> +   bool msaa_is_interleaved = false;
>>> +
>>> +   if (num_samples>  0) {
>>> +      /* Adjust width/height/depth for MSAA */
>>> +      msaa_is_interleaved = msaa_format_is_interleaved(**intel,
>>> format);
>>> +      if (msaa_is_interleaved) {
>>> +         /* Note: since samples are interleaved in a complex pattern
>>> that
>>> +          * repeats for every 2x2 block of pixels, we need to expand
>>> the width
>>> +          * and height to even numbers before the width/height
>>> adjustment,
>>> +          * otherwise some of the samples in the last row and column
>>> will fall
>>> +          * outside the boundary of the texture.
>>> +          */
>>> +         switch (num_samples) {
>>> +         case 4:
>>> +            width = ALIGN(width, 2) * 2;
>>> +            height = ALIGN(height, 2) * 2;
>>> +            break;
>>> +         case 8:
>>> +            width = ALIGN(width, 2) * 4;
>>> +            height = ALIGN(height, 2) * 2;
>>> +            break;
>>> +         default:
>>> +            /* num_samples should already have been quantized to 0, 4,
>>> or
>>> +             * 8.
>>> +             */
>>> +            assert(false);
>>> +         }
>>> +      } else {
>>> +         /* Non-interleaved */
>>> +         depth = num_samples;
>>> +      }
>>>     }
>>>
>>>     mt = intel_miptree_create(intel, GL_TEXTURE_2D, format, 0, 0,
>>> -                            width, height, 1, true, num_samples);
>>> +                            width, height, depth, true, num_samples,
>>> +                             msaa_is_interleaved);
>>>
>>>     return mt;
>>>  }
>>> @@ -552,6 +607,8 @@ intel_miptree_alloc_hiz(struct intel_context *intel,
>>>                          GLuint num_samples)
>>>  {
>>>     assert(mt->hiz_mt == NULL);
>>> +   /* MSAA HiZ surfaces are always interleaved. */
>>> +   bool msaa_is_interleaved = num_samples>  0;
>>>     mt->hiz_mt = intel_miptree_create(intel,
>>>                                       mt->target,
>>>                                       MESA_FORMAT_X8_Z24,
>>> @@ -561,7 +618,8 @@ intel_miptree_alloc_hiz(struct intel_context *intel,
>>>                                       mt->height0,
>>>                                       mt->depth0,
>>>                                       true,
>>> -                                     num_samples);
>>> +                                     num_samples,
>>> +                                     msaa_is_interleaved);
>>>
>>>     if (!mt->hiz_mt)
>>>        return false;
>>> diff --git a/src/mesa/drivers/dri/intel/**intel_mipmap_tree.h
>>> b/src/mesa/drivers/dri/intel/**intel_mipmap_tree.h
>>> index ca1666d..3883d2b 100644
>>> --- a/src/mesa/drivers/dri/intel/**intel_mipmap_tree.h
>>> +++ b/src/mesa/drivers/dri/intel/**intel_mipmap_tree.h
>>> @@ -172,6 +172,26 @@ struct intel_mipmap_tree
>>>     GLuint num_samples;
>>>     bool compressed;
>>>
>>> +   /**
>>> +    * For 1D array, 2D array, cube, and 2D multisampled surfaces on
>>> Gen7: true
>>> +    * if the surface only contains LOD 0, and hence no space is for
>>> LOD's
>>> +    * other than 0 in between array slices.
>>> +    *
>>> +    * Corresponds to the surface_array_spacing bit in
>>> gen7_surface_state.
>>> +    */
>>> +   bool array_spacing_lod0;
>>>
>>
>> It seems like we ought to use ARYSPC_LOD0 mode for all non-mipmapped
>> renderbuffers and textures...it should save memory.  If we did that, I
>> think we could probably just use mt->first_level != mt->last_level rather
>> than adding a new flag.
>>
>> Then again, I haven't thought through all the ramifications of that: I
>> know there's some period of time where the user has defined LOD0, and
>> you're not sure whether they're going to defined LOD1, 2, 3 too or just not
>> do mipmapping.  It would suck to allocate something in
>> ARYSPC_LOD0/non-mipmap-capable mode and then have to redo it.  But maybe we
>> have to redo it already?
>>
>
> I think you're right that we have to redo it anyhow, because even without
> using ARYSPC_LOD0, if we speculatively allocate a texture that just has
> LOD0, then we haven't reserved enough memory for the other mip levels of
> the last array slice.
>
> Your suggestion seems reasonable.  The only thing I can think of that
> might get in the way is if there are restrictions in the bspec requiring us
> to disable ARYSPC_LOD0 at certain times.  I'll try to dig through the bspec
> today and check that.
>

We discussed this further in person yesterday, and decided that it would be
better to wait and do it as a future optimization, on the grounds that
changing the layout of every non-mipmapped array texture is a little more
risk than we want to incur in the middle of this patch series.  I've added
it to a list of items to revisit once the bulk of MSAA is complete.

I also seem to recall that you found a subtlety about ARYSPC_LOD0 in the
bspec yesterday that we'll need to keep in mind when we do revisit this
topic.  Do you remember what that was?  I've forgotten the details.
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