David Airlie has queued up his own work on introducing the "DRM sync objects" concept into DRM-Next for in turn landing with the upcoming Linux 4.13 kernel.

DRM sync objects (syncobj) are a top-level self-contained DRM object containing a pointer to a fence, the fence in turn is updated via command submission ioctls. These sync objects can be passed between processes.

For those not following the previous patch series the past few months, there is this code as well as sync_file interaction support for importing the fence from a sync_file into a DRM sync object. There is also a sync object wait API that is based on the Vulkan wait API, but that work has yet to be merged.

For end-users, long story short, the DRM sync objects can be used for efficiently implementing Vulkan external semaphores (VK_KHX_external_semaphore) in the supported DRM drivers.