Re: [PATCH 0/2] MR970: wined3d: Do not enforce map access for resources with WINED3D_RESOURCE_ACCESS_CPU.

[Jan Sikorski (＠jsikorski)]

> d3d maps of such resources will map the CPU copy, and uploads and downloads can

use a staging BO.

I'm concerned about performance implications of this change. If we use a staging (temporary) BO for downloads, then we're going to stall waiting for the download to complete in `wined3d_texture_vk_download_data`. What's the story here for D3D11_USAGE_STAGING resources?

I understand there's some reason to do this for the GL backend, what motivation there is for the Vulkan change?