It has been brought to the SRU team’s attention that mutter has landed a significant new feature in the 46.1 point release¹.
The GNOME MicroReleaseException policy historically exists on the basis that the GNOME release and testing process broadly matches SRU policy, so duplicating that process by performing a full SRU review on GNOME point releases would be unnecessary work. Since mutter no longer appears to have the same understanding of that process as we do, mutter SRUs will not be covered by the GNOME MRE going forward.
Mutter & GNOME Shell point releases may still be acceptable under the normal micro release process; this can be checked on a case-by-case basis.
¹: Specifically, explicit sync support from this PR.
Reading that was surprising as an outsider, as I think one would naturally assume that gnome-shell and mutter would be the most foundational parts of a “GNOME release”, and would be under more limitations for what is allowed in for what would appear to most folks as a “minor” release.
Does this change mean that the explicit sync patches needed to make Nvidia drivers usable on Wayland and stop the flickering will not land in 24.04? From an end-user perspective, I don’t think this is a new feature so much as a bug fix for one of the largest issues using Nvidia on Linux.
It means that such code landing in 24.04 would depend on being submitted to, and going through, the Stable Release Update process linked to in the original post of this thread.
As I would see it (not an Ubuntu dev, but from an outsider perspective, and I’m sure way oversimplifying), it’s a new feature, not a bug fix, because it’s not that there’s existing code that tries to do something but doesn’t work correctly - it’s new code for a new way of pushing graphics to the screen, which didn’t previously exist in GNOME/Mutter/Wayland/etc.
That carries with it new opportunities for things to go wrong, and the LTS model would generally be opposed to introducing new functionality that breaks things that already work - so it has to be evaluated a lot more strictly.
I’ve been tasked with looking into this, and I don’t want to preempt my own findings.
Currently I am testing 46.1 on four systems (two Intel, two AMD) to get some personal confidence that it is not breaking anything obvious. Though I don’t run any Nvidia systems full time.
Later this month I will analyse the code changes in more detail to better inform my opinion.
I am hoping we can get the full 46.1 46.2 into Noble without dropping anything, but it will take more time, analysis and discussion.