graphics: support depth targets with read-only backing

src/graphics/host_gpu/renderer/debug.cpp

@@ -561,9 +561,10 @@ static void ZCheck(const HW::DepthRenderTarget& z, const HW::DepthControl& dc,
 				     z.depth_view.stencil_write_disable ? "true" : "false");
 			}
 		}
-		EXIT_NOT_IMPLEMENTED(z.z_read_base_addr != z.z_write_base_addr);
+		EXIT_NOT_IMPLEMENTED(!z.depth_view.depth_write_disable &&
+		                     z.z_read_base_addr != z.z_write_base_addr);
 		EXIT_NOT_IMPLEMENTED(z.stencil_read_base_addr != z.stencil_write_base_addr);
-		EXIT_NOT_IMPLEMENTED(z.z_write_base_addr == 0);
+		EXIT_NOT_IMPLEMENTED(!z.depth_view.depth_write_disable && z.z_write_base_addr == 0);
 		if (z.stencil_info.format != Prospero::StencilFormat::kInvalid &&
 		    z.stencil_write_base_addr == 0) {
 			LOGF("\t warning: stencil format is set without a stencil base address, continuing "

src/graphics/host_gpu/renderer/depthRenderTarget.cpp

@@ -177,7 +177,8 @@ void RenderExecutor::ResolveRenderDepthTarget(uint64_t submit_id, RenderCommandB
 	    z.htile_surface.htile_uses_preload_win != 0 || z.htile_surface.preload != 0 ||
 	    z.htile_surface.prefetch_width != 0 || z.htile_surface.prefetch_height != 0 ||
 	    z.htile_surface.dst_outside_zero_to_one != 0 || z.z_read_base_addr == 0 ||
-	    z.z_write_base_addr != z.z_read_base_addr || (z.z_read_base_addr & 0xffffu) != 0 ||
+	    (!z.depth_view.depth_write_disable && z.z_write_base_addr != z.z_read_base_addr) ||
+	    (z.z_read_base_addr & 0xffffu) != 0 ||
 	    dc.zfunc > static_cast<uint8_t>(vk::CompareOp::eAlways)) {
 		DepthFatal("unsupported depth register state");
 	}

tests/ShaderRecompilerComputeTests.cpp

@@ -7491,7 +7491,30 @@ public:
               !texture_cache.GetImage(phased_depth.image_id).usage.depth_target,
           "valid PS5 texture-compatibility policy changed logical depth image "
           "identity or discovery side effects");
+
+      auto read_only_depth_target = phased_depth_target;
+      read_only_depth_target.z_write_base_addr = 0;
+      read_only_depth_target.depth_view.depth_write_disable = true;
+      registers.SetDepthRenderTarget(read_only_depth_target);
+      auto read_only_depth_control = phased_depth_control;
+      read_only_depth_control.z_write_enable = false;
+      registers.SetDepthControl(read_only_depth_control);
+      RenderDepthInfo read_only_depth{};
+      RenderExecutorTestAccess::ResolveRenderDepthTarget(
+          executor, 1, scheduler.Current(), read_only_depth);
+      Require(
+          name, "read-only depth target without write address",
+          read_only_depth.image_id == phased_depth.image_id &&
+              read_only_depth.depth_buffer_vaddr == phased_depth_address &&
+              !read_only_depth.depth_write_enable &&
+              !read_only_depth.AttachmentWriteAspects() &&
+              depth_attachment_layout(read_only_depth) ==
+                  vk::ImageLayout::eDepthStencilReadOnlyOptimal,
+          "a PS5 read-only depth target required a depth write address or "
+          "selected a writable host layout");
+
       registers.SetDepthRenderTarget(phased_depth_target);
+      registers.SetDepthControl(phased_depth_control);
       RenderColorInfo no_color{};
       auto phased_rendering = RenderExecutorTestAccess::AcquireRenderTargets(
           executor, scheduler.Current(), &no_color, 0, phased_depth);