}
}
+/**
+ * This function determines the optimal buffer to use for device
+ * accesses given a VkImageLayout and other pieces of information needed to
+ * make that determination. This does not determine the optimal buffer to
+ * use during a resolve operation.
+ *
+ * NOTE: Some layouts do not support device access.
+ *
+ * @param devinfo The device information of the Intel GPU.
+ * @param image The image that may contain a collection of buffers.
+ * @param aspects The aspect(s) of the image to be accessed.
+ * @param layout The current layout of the image aspect(s).
+ *
+ * @return The primary buffer that should be used for the given layout.
+ */
+enum isl_aux_usage
+anv_layout_to_aux_usage(const struct gen_device_info * const devinfo,
+ const struct anv_image * const image,
+ const VkImageAspectFlags aspects,
+ const VkImageLayout layout)
+{
+ /* Validate the inputs. */
+
+ /* The devinfo is needed as the optimal buffer varies across generations. */
+ assert(devinfo != NULL);
+
+ /* The layout of a NULL image is not properly defined. */
+ assert(image != NULL);
+
+ /* The aspects must be a subset of the image aspects. */
+ assert(aspects & image->aspects && aspects <= image->aspects);
+
+ /* Determine the optimal buffer. */
+
+ /* If there is no auxiliary surface allocated, we must use the one and only
+ * main buffer.
+ */
+ if (image->aux_surface.isl.size == 0)
+ return ISL_AUX_USAGE_NONE;
+
+ /* All images that use an auxiliary surface are required to be tiled. */
+ assert(image->tiling == VK_IMAGE_TILING_OPTIMAL);
+
+ /* On BDW+, when clearing the stencil aspect of a depth stencil image,
+ * the HiZ buffer allows us to record the clear with a relatively small
+ * number of packets. Prior to BDW, the HiZ buffer provides no known benefit
+ * to the stencil aspect.
+ */
+ if (devinfo->gen < 8 && aspects == VK_IMAGE_ASPECT_STENCIL_BIT)
+ return ISL_AUX_USAGE_NONE;
+
+ const bool has_depth = aspects & VK_IMAGE_ASPECT_DEPTH_BIT;
+ const bool color_aspect = aspects == VK_IMAGE_ASPECT_COLOR_BIT;
+
+ /* The following switch currently only handles depth stencil aspects.
+ * TODO: Handle the color aspect.
+ */
+ if (color_aspect)
+ return image->aux_usage;
+
+ switch (layout) {
+
+ /* Invalid Layouts */
+
+ /* According to the Vulkan Spec, the following layouts are valid only as
+ * initial layouts in a layout transition and don't support device access.
+ */
+ case VK_IMAGE_LAYOUT_UNDEFINED:
+ case VK_IMAGE_LAYOUT_PREINITIALIZED:
+ case VK_IMAGE_LAYOUT_RANGE_SIZE:
+ case VK_IMAGE_LAYOUT_MAX_ENUM:
+ unreachable("Invalid image layout for device access.");
+
+
+ /* Transfer Layouts
+ *
+ * This buffer could be a depth buffer used in a transfer operation. BLORP
+ * currently doesn't use HiZ for transfer operations so we must use the main
+ * buffer for this layout. TODO: Enable HiZ in BLORP.
+ */
+ case VK_IMAGE_LAYOUT_GENERAL:
+ case VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL:
+ case VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL:
+ return ISL_AUX_USAGE_NONE;
+
+
+ /* Sampling Layouts */
+ case VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL:
+ assert(!color_aspect);
+ /* Fall-through */
+ case VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL:
+ if (has_depth && anv_can_sample_with_hiz(devinfo->gen, image->samples))
+ return ISL_AUX_USAGE_HIZ;
+ else
+ return ISL_AUX_USAGE_NONE;
+
+ case VK_IMAGE_LAYOUT_PRESENT_SRC_KHR:
+ assert(color_aspect);
+
+ /* On SKL+, the render buffer can be decompressed by the presentation
+ * engine. Support for this feature has not yet landed in the wider
+ * ecosystem. TODO: Update this code when support lands.
+ *
+ * From the BDW PRM, Vol 7, Render Target Resolve:
+ *
+ * If the MCS is enabled on a non-multisampled render target, the
+ * render target must be resolved before being used for other
+ * purposes (display, texture, CPU lock) The clear value from
+ * SURFACE_STATE is written into pixels in the render target
+ * indicated as clear in the MCS.
+ *
+ * Pre-SKL, the render buffer must be resolved before being used for
+ * presentation. We can infer that the auxiliary buffer is not used.
+ */
+ return ISL_AUX_USAGE_NONE;
+
+
+ /* Rendering Layouts */
+ case VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL:
+ assert(color_aspect);
+ unreachable("Color images are not yet supported.");
+
+ case VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL:
+ assert(!color_aspect);
+ return ISL_AUX_USAGE_HIZ;
+ }
+
+ /* If the layout isn't recognized in the exhaustive switch above, the
+ * VkImageLayout value is not defined in vulkan.h.
+ */
+ unreachable("layout is not a VkImageLayout enumeration member.");
+}
+
+
static struct anv_state
alloc_surface_state(struct anv_device *device)
{