[d3d11] Occasional short vertex explosion in Kingdom Come Deliverance

[Blisto91]

Been playing KCD1 a bunch here lately and noticed that occasionally (not often but not super rare either) the game will have what appears to be a brief "blink". A closer look at it via frame stepping in a video it seems like it could be a quick vertex explosion.
At first i thought it was just a game bug but when i started poking at it i noticed that it does not happen with older versions of dxvk. More specifically it seems to reproduce for me since commit 14990db

dxvk.zeroMappedMemory = True as suggested by @doitsujin does seem to work around the issue but i gather that it might incur a performance hit and so isn't desirable to just enable for the game in general.

Running the game with Vulkan Validation Layers showed this error a couple of times

err:   VUID-VkGraphicsPipelineCreateInfo-Input-07904: 
err:   Validation Error: [ VUID-VkGraphicsPipelineCreateInfo-Input-07904 ] | MessageID = 0xcc9c32be | vkCreateGraphicsPipelines(): pCreateInfos[0].pVertexInputState->pVertexAttributeDescriptions does not have a Location 4 but vertex shader has an input variable at that Location.
err:   The Vulkan spec states: If the pipeline is being created with vertex input state and pVertexInputState is not dynamic, then all variables with the Input storage class decorated with Location in the Vertex Execution Model OpEntryPoint must contain a location in VkVertexInputAttributeDescription::location (https://www.khronos.org/registry/vulkan/specs/1.3-extensions/html/vkspec.html#VUID-VkGraphicsPipelineCreateInfo-Input-07904)

Software information

Kingdom Come Deliverance
Ultra High preset + HD Textures.
Vegetation draw distance have been upped slightly so it 6 steps from max limit.

System information

• GPU: RTX 4080
• Driver: 570.86.16
• Wine version: Proton Bleeding Edge
• DXVK version: 14990db and above

Apitrace file(s)

I have tried for multiple hours to catch the issue with apitrace but have sadly been unable to. The game slows down to 0.4fps when tracing which seems to mess with reproduction.

[Blisto91]

The PR above did sadly not help the issue