WIP: RFC: present-timing: Enhanced presentation timing requests and events

This a protocol extension that offers enhanced presentation timing requests and events, in order to help clients minimize visual anomalies.

It is modeled after the VK_KHR_present_timing extension, which was recently published for comments.

Since the Vulkan extension is still largely WIP, changes to that extension which can affect this protocol are quite likely.

There are a few parts of the protocol, copied from the vulkan extension, the utility of which is currently under discussion (e.g., present slop). I have left them in for completeness and the sake of discussion.

The goal of this proposal at this phase is to start an early discussion about the overall approach, and possibly help inform decisions at the Vulkan level, too.

Signed-off-by: Alexandros Frantzis alexandros.frantzis@collabora.com