pvr: Add missing support for preserve attachments

In subpasses preserve attachments are not used by the subpass but
their contents must be preserved throughout the subpass.

Add a list for the preserve attachments info specified by a subpass
and when determining a subpass attachments total uses check the
preserve attachments list and add it uses to the total.

Partial fix for:
dEQP-VK.renderpass.*.attachment_allocation.input_output.71

Backport-to: 26.0

Signed-off-by: Nick Hamilton <nick.hamilton@imgtec.com>
Reviewed-by: Frank Binns <frank.binns@imgtec.com>
(cherry picked from commit 0e01b9ef2d)

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40092>

.pick_status.json

@@ -504,7 +504,7 @@
         "description": "pvr: Add missing support for preserve attachments",
         "nominated": true,
         "nomination_type": 4,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null,
         "notes": null

src/imagination/vulkan/pvr_arch_hw_pass.c

@@ -2290,6 +2290,10 @@ static VkResult pvr_schedule_subpass(const struct pvr_device *device,
                                 subpass_num,
                                 subpass->input_attachments,
                                 subpass->input_count);
+   pvr_dereference_surface_list(ctx,
+                                subpass_num,
+                                subpass->preserve_attachments,
+                                subpass->preserve_count);
    if (subpass->depth_stencil_attachment != VK_ATTACHMENT_UNUSED) {
       struct pvr_render_int_attachment *int_depth_attach =
          &ctx->int_attach[subpass->depth_stencil_attachment];
@@ -2595,6 +2599,11 @@ VkResult pvr_arch_create_renderpass_hwsetup(
                                               subpass->input_count,
                                               i);
 
+         const uint32_t preserve_attachment_uses =
+            pvr_count_uses_in_attachment_list(subpass->preserve_attachments,
+                                              subpass->preserve_count,
+                                              i);
+
          uint32_t resolve_output_uses;
          uint32_t color_output_uses;
          uint32_t total_output_uses;
@@ -2604,13 +2613,13 @@ VkResult pvr_arch_create_renderpass_hwsetup(
                                              &color_output_uses,
                                              &resolve_output_uses);
 
-         total_output_uses = color_output_uses + resolve_output_uses;
+         total_output_uses = color_output_uses + resolve_output_uses +
+                             input_attachment_uses + preserve_attachment_uses;
 
-         if (total_output_uses != 0U || input_attachment_uses != 0U)
+         if (total_output_uses != 0U)
             int_attach->last_read = j;
 
-         int_attach->remaining_count +=
-            total_output_uses + input_attachment_uses;
+         int_attach->remaining_count += total_output_uses;
 
          if ((uint32_t)subpass->depth_stencil_attachment == i)
             int_attach->remaining_count++;

src/imagination/vulkan/pvr_arch_pass.c

@@ -763,7 +763,9 @@ PVR_PER_ARCH(CreateRenderPass2)(VkDevice _device,
    const VkAllocationCallbacks *alloc;
    size_t subpass_attachment_count;
    size_t subpass_input_attachment_count;
+   size_t subpass_preserve_attachment_count;
    struct pvr_render_attachment *subpass_input_attachments;
+   struct pvr_render_attachment *subpass_preserve_attachments;
    uint32_t *subpass_attachments;
    struct pvr_render_pass *pass;
    uint32_t *dep_list;
@@ -785,12 +787,14 @@ PVR_PER_ARCH(CreateRenderPass2)(VkDevice _device,
 
    subpass_attachment_count = 0;
    subpass_input_attachment_count = 0;
+   subpass_preserve_attachment_count = 0;
    for (uint32_t i = 0; i < pCreateInfo->subpassCount; i++) {
       const VkSubpassDescription2 *desc = &pCreateInfo->pSubpasses[i];
       subpass_attachment_count +=
          desc->colorAttachmentCount +
          (desc->pResolveAttachments ? desc->colorAttachmentCount : 0);
       subpass_input_attachment_count += desc->inputAttachmentCount;
+      subpass_preserve_attachment_count += desc->preserveAttachmentCount;
    }
 
    vk_multialloc_add(&ma,
@@ -801,6 +805,10 @@ PVR_PER_ARCH(CreateRenderPass2)(VkDevice _device,
                      &subpass_input_attachments,
                      __typeof__(*subpass_input_attachments),
                      subpass_input_attachment_count);
+   vk_multialloc_add(&ma,
+                     &subpass_preserve_attachments,
+                     __typeof__(*subpass_preserve_attachments),
+                     subpass_preserve_attachment_count);
    vk_multialloc_add(&ma,
                      &dep_list,
                      __typeof__(*dep_list),
@@ -989,6 +997,17 @@ PVR_PER_ARCH(CreateRenderPass2)(VkDevice _device,
          }
       }
 
+      subpass->preserve_count = desc->preserveAttachmentCount;
+      if (subpass->preserve_count > 0) {
+         subpass->preserve_attachments = subpass_preserve_attachments;
+         subpass_preserve_attachments += subpass->preserve_count;
+
+         for (uint32_t j = 0; j < subpass->preserve_count; j++) {
+            subpass->preserve_attachments[j].attachment_idx =
+               desc->pPreserveAttachments[j];
+         }
+      }
+
       /* Give the dependencies a slice of the subpass_attachments array. */
       subpass->dep_list = dep_list;
       dep_list += subpass->dep_count;

src/imagination/vulkan/pvr_pass.h

@@ -71,6 +71,9 @@ struct pvr_render_subpass {
    uint32_t input_count;
    struct pvr_render_attachment *input_attachments;
 
+   uint32_t preserve_count;
+   struct pvr_render_attachment *preserve_attachments;
+
    uint32_t depth_stencil_attachment;
 
    uint32_t depth_stencil_resolve_attachment;