
Jonathan Marek opened the merge request back in August 2020 for moving the Vulkan WSI display code over to using the Linux Direct Rendering Manager atomic mode-setting APIs rather than the "legacy" mode-setting APIs. The Vulkan WSI code within Mesa is common to the different Vulkan hardware drivers.
Besides moving to these APIs that have been well supported by the modern upstream Linux DRM/KMS drivers for years, the other notable advantage of this transition is it being a prerequisite for landing the DRM modifiers support.

For more information on this transition to the atomic mode-setting interfaces for the Vulkan WSI code can be found via this Mesa merge .