src/vulkan/anv_image.c

/*
 * Copyright © 2015 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <assert.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>

#include "anv_private.h"

/* FIXME: We shouldn't be using the actual hardware enum values here.  They
 * change across gens.  Once we get that fixed, this include needs to go.
 */
#include "gen8_pack.h"

static const uint8_t anv_halign[] = {
    [4] = HALIGN4,
    [8] = HALIGN8,
    [16] = HALIGN16,
};

static const uint8_t anv_valign[] = {
    [4] = VALIGN4,
    [8] = VALIGN8,
    [16] = VALIGN16,
};

static const uint8_t anv_surf_type_from_image_type[] = {
   [VK_IMAGE_TYPE_1D] = SURFTYPE_1D,
   [VK_IMAGE_TYPE_2D] = SURFTYPE_2D,
   [VK_IMAGE_TYPE_3D] = SURFTYPE_3D,
};

static const struct anv_image_view_info
anv_image_view_info_table[] = {
   #define INFO(s, ...) { .surface_type = s, __VA_ARGS__ }
   [VK_IMAGE_VIEW_TYPE_1D]          = INFO(SURFTYPE_1D),
   [VK_IMAGE_VIEW_TYPE_2D]          = INFO(SURFTYPE_2D),
   [VK_IMAGE_VIEW_TYPE_3D]          = INFO(SURFTYPE_3D),
   [VK_IMAGE_VIEW_TYPE_CUBE]        = INFO(SURFTYPE_CUBE,                  .is_cube = 1),
   [VK_IMAGE_VIEW_TYPE_1D_ARRAY]    = INFO(SURFTYPE_1D,     .is_array = 1),
   [VK_IMAGE_VIEW_TYPE_2D_ARRAY]    = INFO(SURFTYPE_2D,     .is_array = 1),
   [VK_IMAGE_VIEW_TYPE_CUBE_ARRAY]  = INFO(SURFTYPE_CUBE,   .is_array = 1, .is_cube = 1),
   #undef INFO
};

struct anv_image_view_info
anv_image_view_info_for_vk_image_view_type(VkImageViewType type)
{
   return anv_image_view_info_table[type];
}

static const struct anv_surf_type_limits {
   int32_t width;
   int32_t height;
   int32_t depth;
} anv_surf_type_limits[] = {
   [SURFTYPE_1D]     = {16384,       1,   2048},
   [SURFTYPE_2D]     = {16384,   16384,   2048},
   [SURFTYPE_3D]     = {2048,     2048,   2048},
   [SURFTYPE_CUBE]   = {16384,   16384,    340},
   [SURFTYPE_BUFFER] = {128,     16384,     64},
   [SURFTYPE_STRBUF] = {128,     16384,     64},
};

static const struct anv_tile_info {
   /**
    * Alignment for RENDER_SURFACE_STATE.SurfaceBaseAddress.
    *
    * To simplify calculations, the alignments defined in the table are
    * sometimes larger than required.  For example, Skylake requires that X and
    * Y tiled buffers be aligned to 4K, but Broadwell permits smaller
    * alignment. We choose 4K to accomodate both chipsets.  The alignment of
    * a linear buffer depends on its element type and usage. Linear depth
    * buffers have the largest alignment, 64B, so we choose that for all linear
    * buffers.
    */
   uint32_t surface_alignment;
} anv_tile_info_table[] = {
   [ISL_TILING_LINEAR]  = {   64 },
   [ISL_TILING_X]       = { 4096 },
   [ISL_TILING_Y]       = { 4096 },
   [ISL_TILING_Yf]      = { 4096 },
   [ISL_TILING_Ys]      = { 4096 },
   [ISL_TILING_W]       = { 4096 },
};

static enum isl_tiling
anv_image_choose_tiling(const struct anv_image_create_info *anv_info)
{
   if (anv_info->force_tiling)
      return anv_info->tiling;

   /* The Sandybridge PRM says that the stencil buffer "is supported
    * only in Tile W memory".
    */

   switch (anv_info->vk_info->tiling) {
   case VK_IMAGE_TILING_LINEAR:
      assert(anv_info->vk_info->format != VK_FORMAT_S8_UINT);
      return ISL_TILING_LINEAR;
   case VK_IMAGE_TILING_OPTIMAL:
      if (unlikely(anv_info->vk_info->format == VK_FORMAT_S8_UINT)) {
         return ISL_TILING_W;
      } else {
         return ISL_TILING_Y;
      }
   default:
      assert(!"bad VKImageTiling");
      return ISL_TILING_LINEAR;
   }
}


/**
 * The \a format argument is required and overrides any format in
 * struct anv_image_create_info.
 */
static VkResult
anv_image_make_surface(const struct anv_device *dev,
                       const struct anv_image_create_info *create_info,
                       const struct anv_format *format,
                       uint64_t *inout_image_size,
                       uint32_t *inout_image_alignment,
                       struct anv_surface *out_surface)
{
   /* See RENDER_SURFACE_STATE.SurfaceQPitch */
   static const uint16_t min_qpitch UNUSED = 0x4;
   static const uint16_t max_qpitch UNUSED = 0x1ffc;

   const VkExtent3D *restrict extent = &create_info->vk_info->extent;
   const uint32_t levels = create_info->vk_info->mipLevels;
   const uint32_t array_size = create_info->vk_info->arraySize;
   const enum isl_tiling tiling = anv_image_choose_tiling(create_info);

   const struct anv_tile_info *tile_info =
       &anv_tile_info_table[tiling];

   const uint32_t bs = format->isl_layout->bs;
   const uint32_t bw = format->isl_layout->bw;
   const uint32_t bh = format->isl_layout->bh;

   struct isl_extent2d tile_extent;
   isl_tiling_get_extent(&dev->isl_dev, tiling, bs, &tile_extent);

   const uint32_t i = MAX(4, bw); /* FINISHME: Stop hardcoding subimage alignment */
   const uint32_t j = MAX(4, bh); /* FINISHME: Stop hardcoding subimage alignment */
   assert(i == 4 || i == 8 || i == 16);
   assert(j == 4 || j == 8 || j == 16);

   uint16_t qpitch = min_qpitch;
   uint32_t mt_width = 0;
   uint32_t mt_height = 0;

   switch (create_info->vk_info->imageType) {
   case VK_IMAGE_TYPE_1D:
      /* From the Broadwell PRM >> Memory Views >> Common Surface Formats >>
       * Surface Layout >> 1D Surfaces:
       *
       *    One-dimensional surfaces are identical to 2D surfaces with height of one.
       *
       * So fallthrough...
       */
   case VK_IMAGE_TYPE_2D: {
      const uint32_t w0 = align_u32(extent->width, i);
      const uint32_t h0 = align_u32(extent->height, j);

      if (levels == 1 && array_size == 1) {
         qpitch = min_qpitch;
         mt_width = w0;
         mt_height = h0;
      } else {
         uint32_t w1 = align_u32(anv_minify(extent->width, 1), i);
         uint32_t h1 = align_u32(anv_minify(extent->height, 1), j);
         uint32_t w2 = align_u32(anv_minify(extent->width, 2), i);

         /* The QPitch equation is found in the Broadwell PRM >> Volume 5: Memory
          * Views >> Common Surface Formats >> Surface Layout >> 2D Surfaces >>
          * Surface Arrays >> For All Surface Other Than Separate Stencil Buffer:
          */
         assert(bh ==1 || bh == 4);
         qpitch = (h0 + h1 + 11 * j) / bh;
         mt_width = MAX(w0, w1 + w2);
         mt_height = array_size * qpitch;
      }
      break;
   }
   case VK_IMAGE_TYPE_3D:
      /* The layout of 3D surfaces is described by the Broadwell PRM >>
       * Volume 5: Memory Views >> Common Surface Formats >> Surface Layout >>
       * 3D Surfaces.
       */
      for (uint32_t l = 0; l < levels; ++l) {
         const uint32_t w_l = align_u32(anv_minify(extent->width, l), i);
         const uint32_t h_l = align_u32(anv_minify(extent->height, l), j);
         const uint32_t d_l = anv_minify(extent->depth, l);

         const uint32_t max_layers_horiz = MIN(d_l, 1u << l);
         const uint32_t max_layers_vert = align_u32(d_l, 1u << l) / (1u << l);

         mt_width = MAX(mt_width, w_l * max_layers_horiz);
         mt_height += h_l * max_layers_vert;
      }
      break;
   default:
      unreachable(!"bad VkImageType");
   }

   assert(qpitch >= min_qpitch);
   if (qpitch > max_qpitch) {
      anv_loge("image qpitch > 0x%x\n", max_qpitch);
      return vk_error(VK_ERROR_OUT_OF_DEVICE_MEMORY);
   }

   /* From the Broadwell PRM, RENDER_SURFACE_STATE.SurfaceQpitch:
    *
    *   This field must be set an integer multiple of the Surface Vertical
    *   Alignment.
    */
   assert(anv_is_aligned(qpitch, j));

   uint32_t stride = align_u32(mt_width * bs / bw, tile_extent.width);
   if (create_info->stride > 0)
      stride = create_info->stride;

  /* The padding requirement is found in the Broadwell PRM >> Volume 5: Memory
   * Views >> Common Surface Formats >> Surface Padding Requirements >>
   * Sampling Engine Surfaces >> Buffer Padding Requirements:
   */
   const uint32_t mem_rows = align_u32(mt_height / bh, 2 * bh);
   const uint32_t size = stride * align_u32(mem_rows, tile_extent.height);
   const uint32_t offset = align_u32(*inout_image_size,
                                     tile_info->surface_alignment);

   *inout_image_size = offset + size;
   *inout_image_alignment = MAX(*inout_image_alignment,
                                tile_info->surface_alignment);

   *out_surface = (struct anv_surface) {
      .offset = offset,
      .stride = stride,
      .tiling = tiling,
      .qpitch = qpitch,
      .h_align = i,
      .v_align = j,
   };

   return VK_SUCCESS;
}

static VkImageUsageFlags
anv_image_get_full_usage(const VkImageCreateInfo *info)
{
   VkImageUsageFlags usage = info->usage;

   if (usage & VK_IMAGE_USAGE_TRANSFER_SRC_BIT) {
      /* Meta will transfer from the image by binding it as a texture. */
      usage |= VK_IMAGE_USAGE_SAMPLED_BIT;
   }

   if (usage & VK_IMAGE_USAGE_TRANSFER_DST_BIT) {
      /* Meta will transfer to the image by binding it as a color attachment,
       * even if the image format is not a color format.
       */
      usage |= VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
   }

   return usage;
}

VkResult
anv_image_create(VkDevice _device,
                 const struct anv_image_create_info *create_info,
                 VkImage *pImage)
{
   ANV_FROM_HANDLE(anv_device, device, _device);
   const VkImageCreateInfo *pCreateInfo = create_info->vk_info;
   const VkExtent3D *restrict extent = &pCreateInfo->extent;
   struct anv_image *image = NULL;
   VkResult r;

   assert(pCreateInfo->sType == VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO);

   anv_assert(pCreateInfo->mipLevels > 0);
   anv_assert(pCreateInfo->arraySize > 0);
   anv_assert(pCreateInfo->samples == 1);
   anv_assert(pCreateInfo->extent.width > 0);
   anv_assert(pCreateInfo->extent.height > 0);
   anv_assert(pCreateInfo->extent.depth > 0);

   /* TODO(chadv): How should we validate inputs? */
   const uint8_t surf_type =
      anv_surf_type_from_image_type[pCreateInfo->imageType];

   const struct anv_surf_type_limits *limits =
      &anv_surf_type_limits[surf_type];

   /* Errors should be caught by VkImageFormatProperties. */
   assert(extent->width <= limits->width);
   assert(extent->height <= limits->height);
   assert(extent->depth <= limits->depth);

   image = anv_device_alloc(device, sizeof(*image), 8,
                            VK_SYSTEM_ALLOC_TYPE_API_OBJECT);
   if (!image)
      return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);

   memset(image, 0, sizeof(*image));
   image->type = pCreateInfo->imageType;
   image->extent = pCreateInfo->extent;
   image->format = anv_format_for_vk_format(pCreateInfo->format);
   image->levels = pCreateInfo->mipLevels;
   image->array_size = pCreateInfo->arraySize;
   image->usage = anv_image_get_full_usage(pCreateInfo);
   image->surface_type = surf_type;

   if (image->usage & (VK_IMAGE_USAGE_SAMPLED_BIT |
                       VK_IMAGE_USAGE_STORAGE_BIT)) {
      image->needs_nonrt_surface_state = true;
   }

   if (image->usage & VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT) {
      image->needs_color_rt_surface_state = true;
   }

   if (likely(anv_format_is_color(image->format))) {
      r = anv_image_make_surface(device, create_info, image->format,
                                 &image->size, &image->alignment,
                                 &image->color_surface);
      if (r != VK_SUCCESS)
         goto fail;
   } else {
      if (image->format->depth_format) {
         r = anv_image_make_surface(device, create_info, image->format,
                                    &image->size, &image->alignment,
                                    &image->depth_surface);
         if (r != VK_SUCCESS)
            goto fail;
      }

      if (image->format->has_stencil) {
         r = anv_image_make_surface(device, create_info, anv_format_s8_uint,
                                    &image->size, &image->alignment,
                                    &image->stencil_surface);
         if (r != VK_SUCCESS)
            goto fail;
      }
   }

   *pImage = anv_image_to_handle(image);

   return VK_SUCCESS;

fail:
   if (image)
      anv_device_free(device, image);

   return r;
}

VkResult
anv_CreateImage(VkDevice device,
                const VkImageCreateInfo *pCreateInfo,
                VkImage *pImage)
{
   return anv_image_create(device,
      &(struct anv_image_create_info) {
         .vk_info = pCreateInfo,
      },
      pImage);
}

void
anv_DestroyImage(VkDevice _device, VkImage _image)
{
   ANV_FROM_HANDLE(anv_device, device, _device);

   anv_device_free(device, anv_image_from_handle(_image));
}

static void
anv_surface_get_subresource_layout(struct anv_image *image,
                                   struct anv_surface *surface,
                                   const VkImageSubresource *subresource,
                                   VkSubresourceLayout *layout)
{
   /* If we are on a non-zero mip level or array slice, we need to
    * calculate a real offset.
    */
   anv_assert(subresource->mipLevel == 0);
   anv_assert(subresource->arrayLayer == 0);

   layout->offset = surface->offset;
   layout->rowPitch = surface->stride;
   layout->depthPitch = surface->qpitch;

   /* FINISHME: We really shouldn't be doing this calculation here */
   if (image->array_size > 1)
      layout->size = surface->qpitch * image->array_size;
   else
      layout->size = surface->stride * image->extent.height;
}

VkResult anv_GetImageSubresourceLayout(
    VkDevice                                    device,
    VkImage                                     _image,
    const VkImageSubresource*                   pSubresource,
    VkSubresourceLayout*                        pLayout)
{
   ANV_FROM_HANDLE(anv_image, image, _image);

   switch (pSubresource->aspect) {
   case VK_IMAGE_ASPECT_COLOR:
      anv_surface_get_subresource_layout(image, &image->color_surface,
                                         pSubresource, pLayout);
      break;
   case VK_IMAGE_ASPECT_DEPTH:
      anv_surface_get_subresource_layout(image, &image->depth_surface,
                                         pSubresource, pLayout);
      break;
   case VK_IMAGE_ASPECT_STENCIL:
      anv_surface_get_subresource_layout(image, &image->stencil_surface,
                                         pSubresource, pLayout);
      break;
   default:
      return vk_error(VK_UNSUPPORTED);
   }

   return VK_SUCCESS;
}

VkResult
anv_validate_CreateImageView(VkDevice _device,
                             const VkImageViewCreateInfo *pCreateInfo,
                             VkImageView *pView)
{
   ANV_FROM_HANDLE(anv_image, image, pCreateInfo->image);
   const VkImageSubresourceRange *subresource;
   const struct anv_image_view_info *view_info;
   const struct anv_format *view_format_info;

   /* Validate structure type before dereferencing it. */
   assert(pCreateInfo);
   assert(pCreateInfo->sType == VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO);
   subresource = &pCreateInfo->subresourceRange;

   /* Validate viewType is in range before using it. */
   assert(pCreateInfo->viewType >= VK_IMAGE_VIEW_TYPE_BEGIN_RANGE);
   assert(pCreateInfo->viewType <= VK_IMAGE_VIEW_TYPE_END_RANGE);
   view_info = &anv_image_view_info_table[pCreateInfo->viewType];

   /* Validate format is in range before using it. */
   assert(pCreateInfo->format >= VK_FORMAT_BEGIN_RANGE);
   assert(pCreateInfo->format <= VK_FORMAT_END_RANGE);
   view_format_info = anv_format_for_vk_format(pCreateInfo->format);

   /* Validate channel swizzles. */
   assert(pCreateInfo->channels.r >= VK_CHANNEL_SWIZZLE_BEGIN_RANGE);
   assert(pCreateInfo->channels.r <= VK_CHANNEL_SWIZZLE_END_RANGE);
   assert(pCreateInfo->channels.g >= VK_CHANNEL_SWIZZLE_BEGIN_RANGE);
   assert(pCreateInfo->channels.g <= VK_CHANNEL_SWIZZLE_END_RANGE);
   assert(pCreateInfo->channels.b >= VK_CHANNEL_SWIZZLE_BEGIN_RANGE);
   assert(pCreateInfo->channels.b <= VK_CHANNEL_SWIZZLE_END_RANGE);
   assert(pCreateInfo->channels.a >= VK_CHANNEL_SWIZZLE_BEGIN_RANGE);
   assert(pCreateInfo->channels.a <= VK_CHANNEL_SWIZZLE_END_RANGE);

   /* Validate subresource. */
   assert(subresource->aspectMask != 0);
   assert(subresource->mipLevels > 0);
   assert(subresource->arraySize > 0);
   assert(subresource->baseMipLevel < image->levels);
   assert(subresource->baseMipLevel + subresource->mipLevels <= image->levels);
   assert(subresource->baseArrayLayer < image->array_size);
   assert(subresource->baseArrayLayer + subresource->arraySize <= image->array_size);
   assert(pView);

   if (view_info->is_cube) {
      assert(subresource->baseArrayLayer % 6 == 0);
      assert(subresource->arraySize % 6 == 0);
   }

   const VkImageAspectFlags ds_flags = VK_IMAGE_ASPECT_DEPTH_BIT
                                     | VK_IMAGE_ASPECT_STENCIL_BIT;

   /* Validate format. */
   if (subresource->aspectMask & VK_IMAGE_ASPECT_COLOR_BIT) {
      assert(subresource->aspectMask == VK_IMAGE_ASPECT_COLOR_BIT);
      assert(!image->format->depth_format);
      assert(!image->format->has_stencil);
      assert(!view_format_info->depth_format);
      assert(!view_format_info->has_stencil);
      assert(view_format_info->isl_layout->bs ==
             image->format->isl_layout->bs);
   } else if (subresource->aspectMask & ds_flags) {
      assert((subresource->aspectMask & ~ds_flags) == 0);

      if (subresource->aspectMask & VK_IMAGE_ASPECT_STENCIL_BIT) {
         assert(image->format->depth_format);
         assert(view_format_info->depth_format);
         assert(view_format_info->isl_layout->bs ==
                image->format->isl_layout->bs);
      }

      if (subresource->aspectMask & VK_IMAGE_ASPECT_STENCIL) {
         /* FINISHME: Is it legal to have an R8 view of S8? */
         assert(image->format->has_stencil);
         assert(view_format_info->has_stencil);
      }
   } else {
      assert(!"bad VkImageSubresourceRange::aspectFlags");
   }

   return anv_CreateImageView(_device, pCreateInfo, pView);
}

void
anv_image_view_init(struct anv_image_view *iview,
                    struct anv_device *device,
                    const VkImageViewCreateInfo* pCreateInfo,
                    struct anv_cmd_buffer *cmd_buffer)
{
   ANV_FROM_HANDLE(anv_image, image, pCreateInfo->image);
   const VkImageSubresourceRange *range = &pCreateInfo->subresourceRange;

   assert(range->arraySize > 0);
   assert(range->baseMipLevel < image->levels);
   assert(image->usage & (VK_IMAGE_USAGE_SAMPLED_BIT |
                          VK_IMAGE_USAGE_STORAGE_BIT |
                          VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT |
                          VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT));

   switch (image->type) {
   default:
      unreachable("bad VkImageType");
   case VK_IMAGE_TYPE_1D:
   case VK_IMAGE_TYPE_2D:
      assert(range->baseArrayLayer + range->arraySize - 1 <= image->array_size);
      break;
   case VK_IMAGE_TYPE_3D:
      assert(range->baseArrayLayer + range->arraySize - 1
             <= anv_minify(image->extent.depth, range->baseMipLevel));
      break;
   }

   switch (device->info.gen) {
   case 7:
      if (device->info.is_haswell)
         gen75_image_view_init(iview, device, pCreateInfo, cmd_buffer);
      else
         gen7_image_view_init(iview, device, pCreateInfo, cmd_buffer);
      break;
   case 8:
      gen8_image_view_init(iview, device, pCreateInfo, cmd_buffer);
      break;
   case 9:
      gen9_image_view_init(iview, device, pCreateInfo, cmd_buffer);
      break;
   default:
      unreachable("unsupported gen\n");
   }
}

VkResult
anv_CreateImageView(VkDevice _device,
                    const VkImageViewCreateInfo *pCreateInfo,
                    VkImageView *pView)
{
   ANV_FROM_HANDLE(anv_device, device, _device);
   struct anv_image_view *view;

   view = anv_device_alloc(device, sizeof(*view), 8,
                           VK_SYSTEM_ALLOC_TYPE_API_OBJECT);
   if (view == NULL)
      return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);

   anv_image_view_init(view, device, pCreateInfo, NULL);

   *pView = anv_image_view_to_handle(view);

   return VK_SUCCESS;
}

static void
anv_image_view_destroy(struct anv_device *device,
                       struct anv_image_view *iview)
{
   if (iview->image->needs_color_rt_surface_state) {
      anv_state_pool_free(&device->surface_state_pool,
                          iview->color_rt_surface_state);
   }

   if (iview->image->needs_nonrt_surface_state) {
      anv_state_pool_free(&device->surface_state_pool,
                          iview->nonrt_surface_state);
   }

   anv_device_free(device, iview);
}

void
anv_DestroyImageView(VkDevice _device, VkImageView _iview)
{
   ANV_FROM_HANDLE(anv_device, device, _device);
   ANV_FROM_HANDLE(anv_image_view, iview, _iview);

   anv_image_view_destroy(device, iview);
}

struct anv_surface *
anv_image_get_surface_for_aspect_mask(struct anv_image *image, VkImageAspectFlags aspect_mask)
{
   switch (aspect_mask) {
   case VK_IMAGE_ASPECT_COLOR_BIT:
      /* Dragons will eat you.
       *
       * Meta attaches all destination surfaces as color render targets. Guess
       * what surface the Meta Dragons really want.
       */
      if (image->format->depth_format && image->format->has_stencil) {
         anv_finishme("combined depth stencil formats");
         return &image->depth_surface;
      } else if (image->format->depth_format) {
         return &image->depth_surface;
      } else if (image->format->has_stencil) {
         return &image->stencil_surface;
      } else {
         return &image->color_surface;
      }
      break;
   case VK_IMAGE_ASPECT_DEPTH_BIT:
      assert(image->format->depth_format);
      return &image->depth_surface;
   case VK_IMAGE_ASPECT_STENCIL_BIT:
      assert(image->format->has_stencil);
      return &image->stencil_surface;
   case VK_IMAGE_ASPECT_DEPTH_BIT | VK_IMAGE_ASPECT_STENCIL_BIT:
      if (image->format->depth_format && image->format->has_stencil) {
         /* FINISHME: The Vulkan spec (git a511ba2) requires support for combined
          * depth stencil formats. Specifically, it states:
          *
          *    At least one of ename:VK_FORMAT_D24_UNORM_S8_UINT or
          *    ename:VK_FORMAT_D32_SFLOAT_S8_UINT must be supported.
          */
         anv_finishme("combined depthstencil aspect");
         return &image->depth_surface;
      } else if (image->format->depth_format) {
         return &image->depth_surface;
      } else if (image->format->has_stencil) {
         return &image->stencil_surface;
      }
      /* fallthrough */
    default:
       unreachable("image does not have aspect");
       return NULL;
   }
}

#if 0
   VkImageAspectFlags aspect_mask = 0;
   if (format->depth_format)
      aspect_mask |= VK_IMAGE_ASPECT_DEPTH_BIT;
   if (format->has_stencil)
      aspect_mask |= VK_IMAGE_ASPECT_STENCIL_BIT;
   if (!aspect_mask)
      aspect_mask |= VK_IMAGE_ASPECT_COLOR_BIT;

   anv_image_view_init(iview, device,
      &(VkImageViewCreateInfo) {
         .sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO,
         .image = info->image,
         .viewType = VK_IMAGE_VIEW_TYPE_2D,
         .format = info->format,
         .channels = {
            .r = VK_CHANNEL_SWIZZLE_R,
            .g = VK_CHANNEL_SWIZZLE_G,
            .b = VK_CHANNEL_SWIZZLE_B,
            .a = VK_CHANNEL_SWIZZLE_A,
         },
         .subresourceRange = {
            .aspectMask = aspect_mask,
            .baseMipLevel = info->mipLevel,
            .mipLevels = 1,
            .baseArrayLayer = info->baseArraySlice,
            .arraySize = info->arraySize,
         },
      },
      NULL);
#endif