[Mesa-dev] [RFC] Concrete proposal to split classic

[Eric Anholt]

On Mon, Mar 22, 2021 at 3:27 PM Dylan Baker <dylan at pnwbakers.com> wrote:
>
> Hi list,
>
> We've talked about it a number of times, but I think it's time time to
> discuss splitting the classic drivers off of the main development branch
> again, although this time I have a concrete plan for how this would
> work.
>
> First, why? Basically, all of the classic drivers are in maintanence
> mode (even i965). Second, many of them rely on code that no one works
> on, and very few people still understand. There is no CI for most of
> them, and the Intel CI is not integrated with gitlab, so it's easy to
> unintentionally break them, and this breakage usually isn't noticed
> until just before or just after a release. 21.0 was held up (in small
> part, also me just getting behind) because of such breakages.
>
> I konw there is some interest in getting i915g in good enough shape that
> it could replace i915c, at least for the common case. I also am aware
> that Dave, Ilia, and Eric (with some pointers from Ken) have been
> working on a gallium driver to replace i965. Neither of those things are
> ready yet, but I've taken them into account.
>
> Here's the plan:
>
> 1) 21.1 release happens
> 2) we remove classic from master
> 3) 21.1 reaches EOL because of 21.2
> 4) we fork the 21.1 branch into a "classic-lts"¹ branch
> 5) we disable all vulkan and gallium drivers in said branch, at least at
>    the Meson level
> 6) We change the name and precidence of the glvnd loader file
> 7) apply any build fixups (turn of intel generators for versions >= 7.5,
>    for example
> 8) maintain that branch with build and critical bug fixes only

I would like it if Intel could avoid garbage-collecting older-HW
shared code for at least a release due aforementioned WIPs, but I
think it's time to call the classic i965_dri.so and i915_dri.so done.

+1 from me assuming that we validate that one can actually get a
working X server with the mesa-legacy set installed.