diff --git a/include/vkd3d_d3d12.idl b/include/vkd3d_d3d12.idl
index 231123bd..a1f87b22 100644
--- a/include/vkd3d_d3d12.idl
+++ b/include/vkd3d_d3d12.idl
@@ -45,6 +45,8 @@ const UINT D3D12_DEFAULT_STENCIL_WRITE_MASK = 0xff;
 const UINT D3D12_DESCRIPTOR_RANGE_OFFSET_APPEND = 0xffffffff;
 cpp_quote("#define D3D12_FLOAT32_MAX (3.402823466e+38f)")
 const UINT D3D12_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT = 32;
+const UINT D3D12_REQ_CONSTANT_BUFFER_ELEMENT_COUNT = 4096;
+const UINT D3D12_REQ_IMMEDIATE_CONSTANT_BUFFER_ELEMENT_COUNT = 4096;
 const UINT D3D12_REQ_MIP_LEVELS = 15;
 const UINT D3D12_REQ_TEXTURE1D_ARRAY_AXIS_DIMENSION = 2048;
 const UINT D3D12_REQ_TEXTURE1D_U_DIMENSION = 16384;
diff --git a/tests/d3d12.c b/tests/d3d12.c
index 5ae8511f..44e128a9 100644
--- a/tests/d3d12.c
+++ b/tests/d3d12.c
@@ -15387,7 +15387,7 @@ static void test_descriptors_visibility(void)
     destroy_test_context(&context);
 }
 
-static void test_null_descriptors(void)
+static void test_create_null_descriptors(void)
 {
     D3D12_UNORDERED_ACCESS_VIEW_DESC uav_desc;
     D3D12_CONSTANT_BUFFER_VIEW_DESC cbv_desc;
@@ -15456,6 +15456,117 @@ static void test_null_descriptors(void)
     destroy_test_context(&context);
 }
 
+static void test_null_cbv(void)
+{
+    D3D12_ROOT_SIGNATURE_DESC root_signature_desc;
+    D3D12_CONSTANT_BUFFER_VIEW_DESC cbv_desc;
+    ID3D12GraphicsCommandList *command_list;
+    D3D12_ROOT_PARAMETER root_parameters[2];
+    D3D12_DESCRIPTOR_RANGE descriptor_range;
+    struct test_context_desc desc;
+    struct test_context context;
+    ID3D12DescriptorHeap *heap;
+    ID3D12CommandQueue *queue;
+    ID3D12Device *device;
+    unsigned int index;
+    HRESULT hr;
+
+    static const float white[] = {1.0f, 1.0f, 1.0f, 1.0f};
+    static const DWORD ps_code[] =
+    {
+#if 0
+        uint index;
+
+        cbuffer null_cb
+        {
+            float4 data[1024];
+        };
+
+        float4 main() : SV_Target
+        {
+            return data[index];
+        }
+#endif
+        0x43425844, 0xa69026e2, 0xccf934be, 0x11f0a922, 0x95e9ab51, 0x00000001, 0x000000f0, 0x00000003,
+        0x0000002c, 0x0000003c, 0x00000070, 0x4e475349, 0x00000008, 0x00000000, 0x00000008, 0x4e47534f,
+        0x0000002c, 0x00000001, 0x00000008, 0x00000020, 0x00000000, 0x00000000, 0x00000003, 0x00000000,
+        0x0000000f, 0x545f5653, 0x65677261, 0xabab0074, 0x58454853, 0x00000078, 0x00000050, 0x0000001e,
+        0x0100086a, 0x04000059, 0x00208e46, 0x00000000, 0x00000001, 0x04000859, 0x00208e46, 0x00000001,
+        0x00000400, 0x03000065, 0x001020f2, 0x00000000, 0x02000068, 0x00000001, 0x06000036, 0x00100012,
+        0x00000000, 0x0020800a, 0x00000000, 0x00000000, 0x07000036, 0x001020f2, 0x00000000, 0x04208e46,
+        0x00000001, 0x0010000a, 0x00000000, 0x0100003e,
+    };
+    static const D3D12_SHADER_BYTECODE ps = {ps_code, sizeof(ps_code)};
+
+    memset(&desc, 0, sizeof(desc));
+    desc.no_root_signature = true;
+    if (!init_test_context(&context, &desc))
+        return;
+    command_list = context.list;
+    queue = context.queue;
+    device = context.device;
+
+    descriptor_range.RangeType = D3D12_DESCRIPTOR_RANGE_TYPE_CBV;
+    descriptor_range.NumDescriptors = 1;
+    descriptor_range.BaseShaderRegister = 1;
+    descriptor_range.RegisterSpace = 0;
+    descriptor_range.OffsetInDescriptorsFromTableStart = 0;
+    root_parameters[0].ParameterType = D3D12_ROOT_PARAMETER_TYPE_DESCRIPTOR_TABLE;
+    root_parameters[0].DescriptorTable.NumDescriptorRanges = 1;
+    root_parameters[0].DescriptorTable.pDescriptorRanges = &descriptor_range;
+    root_parameters[0].ShaderVisibility = D3D12_SHADER_VISIBILITY_PIXEL;
+
+    root_parameters[1].ParameterType = D3D12_ROOT_PARAMETER_TYPE_32BIT_CONSTANTS;
+    root_parameters[1].Constants.ShaderRegister = 0;
+    root_parameters[1].Constants.RegisterSpace = 0;
+    root_parameters[1].Constants.Num32BitValues = 1;
+    root_parameters[1].ShaderVisibility = D3D12_SHADER_VISIBILITY_PIXEL;
+
+    memset(&root_signature_desc, 0, sizeof(root_signature_desc));
+    root_signature_desc.NumParameters = ARRAY_SIZE(root_parameters);
+    root_signature_desc.pParameters = root_parameters;
+    hr = create_root_signature(device, &root_signature_desc, &context.root_signature);
+    ok(hr == S_OK, "Failed to create root signature, hr %#x.\n", hr);
+
+    context.pipeline_state = create_pipeline_state(context.device,
+            context.root_signature, context.render_target_desc.Format, NULL, &ps, NULL);
+
+    heap = create_gpu_descriptor_heap(device, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, 16);
+
+    cbv_desc.BufferLocation = 0;
+    cbv_desc.SizeInBytes = 0; /* Size doesn't appear to matter for NULL CBV. */
+    ID3D12Device_CreateConstantBufferView(device, &cbv_desc,
+            ID3D12DescriptorHeap_GetCPUDescriptorHandleForHeapStart(heap));
+
+    for (index = 0; index < 1200; index += 100)
+    {
+        ID3D12GraphicsCommandList_ClearRenderTargetView(command_list, context.rtv, white, 0, NULL);
+
+        ID3D12GraphicsCommandList_OMSetRenderTargets(command_list, 1, &context.rtv, FALSE, NULL);
+        ID3D12GraphicsCommandList_SetGraphicsRootSignature(command_list, context.root_signature);
+        ID3D12GraphicsCommandList_SetPipelineState(command_list, context.pipeline_state);
+        ID3D12GraphicsCommandList_SetDescriptorHeaps(command_list, 1, &heap);
+        ID3D12GraphicsCommandList_SetGraphicsRootDescriptorTable(command_list, 0,
+                ID3D12DescriptorHeap_GetGPUDescriptorHandleForHeapStart(heap));
+        ID3D12GraphicsCommandList_SetGraphicsRoot32BitConstants(command_list, 1, 1, &index, 0);
+        ID3D12GraphicsCommandList_IASetPrimitiveTopology(command_list, D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
+        ID3D12GraphicsCommandList_RSSetViewports(command_list, 1, &context.viewport);
+        ID3D12GraphicsCommandList_RSSetScissorRects(command_list, 1, &context.scissor_rect);
+        ID3D12GraphicsCommandList_DrawInstanced(command_list, 3, 1, 0, 0);
+
+        transition_sub_resource_state(command_list, context.render_target, 0,
+                D3D12_RESOURCE_STATE_RENDER_TARGET, D3D12_RESOURCE_STATE_COPY_SOURCE);
+        check_sub_resource_float(context.render_target, 0, queue, command_list, 0x00000000, 0);
+
+        reset_command_list(command_list, context.allocator);
+        transition_sub_resource_state(command_list, context.render_target, 0,
+                D3D12_RESOURCE_STATE_COPY_SOURCE, D3D12_RESOURCE_STATE_RENDER_TARGET);
+    }
+
+    ID3D12DescriptorHeap_Release(heap);
+    destroy_test_context(&context);
+}
+
 #define check_copyable_footprints(a, b, c, d, e, f, g, h) \
         check_copyable_footprints_(__LINE__, a, b, c, d, e, f, g, h)
 static void check_copyable_footprints_(unsigned int line, const D3D12_RESOURCE_DESC *desc,
@@ -25371,7 +25482,8 @@ START_TEST(d3d12)
     run_test(test_copy_descriptors);
     run_test(test_copy_descriptors_range_sizes);
     run_test(test_descriptors_visibility);
-    run_test(test_null_descriptors);
+    run_test(test_create_null_descriptors);
+    run_test(test_null_cbv);
     run_test(test_get_copyable_footprints);
     run_test(test_depth_stencil_sampling);
     run_test(test_depth_load);