On Wed, Mar 24, 2021 at 10:28 AM Rob Clark <robdcl...@gmail.com> wrote: > > On Mon, Mar 22, 2021 at 3:15 PM Dylan Baker <dy...@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 > > I'm +1 for the -lts branch.. the layering between mesa "classic" and > gallium is already starting to get poked thru in the name of > performance, and we've already discovered cases of classic drivers > being broken for multiple months with no one noticing. I think a > slower moving -lts branch is the best approach to keeping things > working for folks with older hw. > > But possibly there is some value in not completely disabling gallium > completely in the -lts branch. We do have some older gallium drivers > which do not have CI coverage and I think are not used frequently by > developers who are tracking the latest main/master branch. I'm not > suggesting that we remove them from the main (non-lts) branch but it > might be useful to be able to recommend users of those drivers stick > with the -lts version for better stability?
I agree with this. Generally, I don't think we should delete anything from the -lts branch. Doing so only risks more breakage. We probably want to change some meson build defaults to not build anything but old drivers but that's it. --Jason > BR, > -R > > > 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 > > > > This gives ditros and end users two options. > > 1) then can build *only* the legacy branch in the a normal Mesa provides > > libGL interfaces fashion > > 2) They can use glvnd and install current mesa and the legacy branch in > > parallel > > > > Because of glvnd, we can control which driver will get loaded first, and > > thus if we decide i915g or the i965 replacement is ready and turn it on > > by default it will be loaded by default. An end user who doesn't like > > this can add a new glvnd loader file that makes the classic drivers > > higher precident and continue to use them. > > > > Why fork from 21.1 instead of master? > > > > First, it allows us to delete classic immediately, which will allow > > refactoring to happen earlier in the cycle, and for any fallout to be > > caught and hopefully fixed before the release. Second, it means that > > when a user is switched from 21.1 to the new classic-lts branch, there > > will be no regressions, and no one has to spend time figuring out what > > broke and fixing the lts branch. > > > > When you say "build and critical bug fixes", what do you mean? > > > > I mean update Meson if we rely on something that in the future is > > deprecated and removed, and would prevent building the branch or an > > relying on some compiler behavior that changes, gaping exploitable > > security holes, that kind of thing. > > > > footnotes > > ¹Or whatever color you like your > > bikeshed_______________________________________________ > > mesa-dev mailing list > > mesa-dev@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/mesa-dev > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
