Vulkan 1.1 spec unclear about VkPhysicalDeviceVulkan11Properties

[kusma]

The Vulkan 1.2 spec says the following about VkPhysicalDeviceVulkan11Features

// Provided by VK_VERSION_1_2
typedef struct VkPhysicalDeviceVulkan11Features {
[...]

That seems strange, as this seems to be intended to declare Vulkan 1.1 features. There's other mentions of the spec in the VK 1.1 spec, though, for instance in the SPIR-V capabilities section, where we can find this:

DrawParameters
VkPhysicalDeviceVulkan11Features::shaderDrawParameters
VK_KHR_shader_draw_parameters

But the features-shaderDrawParameters fragment only talks about VkPhysicalDeviceShaderDrawParametersFeatures, and not VkPhysicalDeviceVulkan11Features...

Here's two possibilities I could imagine that this could mean:

1. Lacking a proper spec for VkPhysicalDeviceVulkan11Features is a bug in the Vulkan 1.1 spec, and it should be included there as well
2. All references to VkPhysicalDeviceVulkan11Features in the Vulkan 1.1 spec are a bug in the spec, and the struct was introduced in Vulkan 1.2 to express Vulkan 1.1 features in a uniform way.

So what is it? Is VkPhysicalDeviceVulkan11Features a part of the Vulkan 1.1 spec or not? In either case, it seems there's a spec bug here, because the functionality is referenced to by several names around the spec.

Right now, this is causing some confusing in Zink, where we're unsure if we currently depend on Vulkan 1.1 or Vulkan 1.2 for OpenGL 4.2 support... See this thread for details.

[pdaniell-nv]

VkPhysicalDeviceVulkan11Features was introduced in Vulkan 1.2 to consolidate a bunch of features that were included into Vulkan 1.1 core. A spec built for Vulkan 1.1 should not mention VkPhysicalDeviceVulkan11Features, if so that's a bug in the spec source.

[oddhack]

The SPIR-V capabilities tables are automatically generated based on tagging in the XML and I think some of the tagging is for the wrong API version, as in this case. Will take this under advisement. I don't believe there are any other references to this structure in the 1.1-extensions spec.

@sfricke-samsung is this something you could look at, since I think you did all this to begin with? I see stuff in the spirvcapabilities section of the XML looking like

        <enable struct="VkPhysicalDeviceVulkan11Features" feature="variablePointersStorageBuffer" requires="VK_VERSION_1_1,VK_KHR_variable_pointers"/>

and that just looks like a typo in the version requirement.

[kusma]

@pdaniell-nv: OK, thanks for the clarification!

[oddhack]

@sfricke-samsung NM, it looked easy so I took a swing at it. Can discuss on the teleconference today.

[oddhack]

This should be fixed in the 1.2.173 spec update.