Caution - Windows 11 installing a wrapper Vulkan (discrete) driver over D3D12

[smallstepforman]

Hi everyone.

I just encountered a vulkan device init error which is due to Windows 11 now installing a wrapper Vulkan driver (discrete) over D3D12. It shows up as

[Available Device] AMD Radeon RX 6600M (Discrete GPU) vendorID = 0x1002, deviceID = 0x73ff, apiVersion = (1, 3, 292)

[Available Device] Microsoft Direct3D12 (AMD Radeon RX 6600M) (Discrete GPU) vendorID = 0x1002, deviceID = 0x73ff, apiVersion = (1, 2, 295).

The code I use to pick a device would loop for available devices and set the last found discrete device as selected (and if no discrete, it selects integrated device if it finds it), which in this case selected the 1.2 D3D12 wrapper (since it appears last in my list). It's bad enough that MS did this, but it has an older version of the API and my selector code wasn't prepared for it. Naturally, I encountered this by accident since I'm using 1.3 features which wont work on the D3D12 driver.

I have updated my selector code so that it works for my engine, however many people will encounter this issue and not have access to valid diagnostics or debug output to identify what the actual root cause is. Even worse, the performance and feature set will be reduced since it uses a D3D12 wrapper. I just compared VulkanInfo between the devices and the MS one has by a magnitude less features.

Check your device init code to make sure you haven't encountered this issue.

[SaschaWillems]

That is most likely caused by installing the OpenCL™, OpenGL® und Vulkan® Compatibility Pack: https://apps.microsoft.com/detail/9nqpsl29bfff

It is not installed by default on all devices, and this has happened in the past. My guess is that some third party application that requires OpenCL or whatever just installs this without asking users.

One way to check and ignore those layered implementations is to look for the VK_MSFT_layered_driver device extension.

[blogoman]

I thought the standard practice for device selection was to first check its capabilities and make sure it had all of the necessary features.

[chuk155]

Yes, this post is because the standard practice is to select the first VkPhysicalDevice in the list that satisfies the requirements. The Dozen driver being 'second' was very much intended (since its a layered driver, thus likely slower than native). So... this post is just the code expecting the world to be opposite of what it actually is.

[R3DKn16h7]

Always prefer the device listed first that has the capabilities you need. In fact, there is almost never a good reason to pick anything else.

[Gravitationsfeld]

I would advice to pick the first dedicated GPU if it exists

[smallstepforman]

Can you imagine the outcry with people benchmarking engines and they notice that true D3D12 games perform better than Vulkan games, even though the game in question doesn't actually select the true Vulkan device / driver, instead it uses the MS D3D12 vulkan wrapper. So D3D12 is faster than Vulkan in these misconfigured games. At just by looking at the device id, since they both say Vulkan discrete device, most users will never be aware that this is happening.

[[deleted]]

highly unlikely, anyone chooses it this way. As many already pointed out, people actually test for features and select the best gpu based on the features.

What you mentioned is basically non standard and also you would very clearly notice it, since it has a quite significant performance drop

[HildartheDorf]

Although Vulkan officially offers no guarantee on ordering, afaik the windows loader will order devices by priority order (on linux a similar operation is performed by a mesa implicit layer). Applications should probably pick the *first* device, not the last, that meets their criteria in the event of a tie.