On Wed, Mar 19, 2025 at 08:57:38AM +0100, Nowa Ammerlaan wrote: > On 19/03/2025 02:07, Ionen Wolkens wrote: > > On Tue, Mar 18, 2025 at 08:34:43PM -0400, Ionen Wolkens wrote: > >> On Tue, Mar 18, 2025 at 03:14:13AM -0000, Duncan wrote: > >>> Nowa Ammerlaan posted on Mon, 17 Mar 2025 11:11:06 +0100 as excerpted: > >>> > >>>> I had really hoped to receive more comments on my earlier RFC. [...] > >>>> I really do want to know what others think so I can > >>>> make a better judgment on whether or not my idea is really this crazy > >>>> and if I should just shut up about it or not (so dear reader if you have > >>>> an opinion then please share). > >>> > >>> So because I carried over my own already "works for me" kernel maintenance > >>> scripts from Mandrake when I switched in 2004 and have continued > >>> maintaining and using them over the decades since, I normally try to stay > >>> out of Gentoo kernel packaging discussion. But given both the above > >>> explicit invitation and that as I've read the thread a thought occurred to > >>> me... > >>> > >>> First, DKMS /is/ a cross-distro standard solution. As such, I believe in > >>> general it should be reasonably supported in Gentoo unless it simply > >>> doesn't make sense (note that "doesn't make sense" can also include the > >>> case of simply no one stepping up to do it, not the case here). > >>> > >>> But, the thought that occurred to me reading the thread, was that there > >>> are obvious parallels between this and another very significant and > >>> controversial now "cross distro standard solution" (which I guess I don't > >>> need to name explicitly). > >>> > >>> As there, I believe "the Gentoo approach" should (again assuming developer > >>> willingness to do the work, seemingly the case here) make it available as > >>> an additional integrated *option*, while keeping the current Gentoo option > >>> as well. > >>> > >>> So I support DKMS integration /as/ /an/ /option/. > >> > >> If anything, if go forward with this, I'd rather that it be with the > >> plan to (eventually) either make it the default after enough testing > >> and then later drop support for the old way entirely (then merge the > >> eclasses), or revert if we think it's no good. > > As I have already stated elsewhere, DKMS can do things that we cannot > achieve with the package manager, and the package manager can do things > that we cannot achieve with DKMS. Each pathway has its use cases. And > for that reason DKMS is not a replacement for the package manager. Nor > can I think of a possible future package manager based solution that can > fully replace what DKMS does (though who knows, maybe someone will prove > me wrong in 20 years) > > This dual-approach is not controversial either, other distributions > often offer a "normal" package as well as a DKMS package. Now since we > have USE flags we do not have to make two separate packages, but > nonetheless the core of letting the user choose to use DKMS or not > remains the same. > > >> One of the thing I did not like here is the idea to gain more ways > >> to do the same thing that need to be tested to ensure some quality. > >> Can't ignore it and leave it all to Nowa given if e.g. nvidia changes > >> some path or something else and I don't test it on bump, then I push > >> a broken package for all dkms users until someone reports it. Would > >> even need to boot with it to be sure. > > I'll grant that you'd indeed have to test both USE=dkms and USE=-dkms, > especially if the ebuild does not use a modlist and therefore the > dkms.conf is not constructed fully automatically. Though I do not see > why this would require actually rebooting the system for both cases. > DKMS either builds and installs the module successfully in postinst or > it does not. And regardless of who did the module installing, it either > loads successfully or it does not. Note that we are intentionally using > the exact same commands to actually build the module in DKMS. > > I'll also note again that Nvidia is one of the upstreams that supports > DKMS, in contrast to our own linux-mod-r1 solution in portage which I > don't think they care about at all. I'd therefore say that it is far > more likely for Nvidia to change something that breaks the existing > non-dkms pathway in the ebuild, then it is for them to break the dkms > pathway that lots of other distributions rely on. > > >> It's nice to have choices in general, but still need to draw some > >> lines to keep things maintainable. > > This maintainability argument would be a lot stronger if I was > reinventing the wheel and proposing some custom Gentoo specific solution > to the problem at hand. Note though that this is not what I am doing (in > fact one could even turn that around and say that this is what you are > doing). You are of course right that more options means more things to > test. But really, it's not a lot of work, I know because I did the work > for almost all of the kernel module ebuilds we have in ::gentoo and was > finished in half a day. The bulk of the work was designing and writing > the eclass and figuring out all the different cases that should be > supported, that part is done now. > > >> And if picking, in the end do we pick an option that requires to > >> install sources and (imo) adds very little, or let the PM (that has > >> access to sources unlike binary distros) handle it (with full control > >> for handling issues) just like for dist kernels and improve on that > >> as needed? > >> > >> Either way, as I said initially, I won't revert if this gets merged > >> (even if optional forever). Just stating that I don't like it and > >> probably won't offer real support, not blocking it. > >> > >> wrt merging eclasses, could add that I wasn't really against the > >> support for this being in linux-mod-r1 directly except for the part > >> where it did not work when not using modlist being confusing, in the > >> end I'd probably just have asked for Nowa to add themselves as > >> maintainer. > > The main reason this is in a separate eclass is because we need a > pkg_prerm for dkms that linux-mod-r1 does not have. And as you pointed > out earlier, exporting an extra phase function in an established eclass > is not a good idea.
Yes, but it could've either have become a linux-mod-r2 (and deprecate -r1 eventually) or done on EAPI bump in the future. I don't really see why any ebuilds should inherit linux-mod-r1 right now when they'll just be the odd one out if they don't support dkms. May as well merge it into dkms.eclass and get rid of it after consumers are gone. On that note, please just take over linux-mod-r1 maintenance if merge this so that I won't have to care anymore. > > >> On a related note about modlist, I've been semi-regretting keeping that > >> modlist-type idea from the original linux-mod eclass and felt that a > >> simple emake wrapper (incl. modules args) for all packages "might" have > >> been better and easier to use for ebuilds and not miss modules on bump > >> and had been pondering "potential" deprecation in the future (not that > >> I had really explored that idea yet, would need to check packages). > > > > (this was in my notes of things to consider for EAPI 9, but likely won't > > try if there is another eclass built upon linux-mod-r1 that I need to > > not break) > > Note that none of this hard requires the modlist. The requirement is > that we have one or more dkms.conf files. These may be provided by > upstream (as is the case for nvidia-drivers), or generated by some build > system script (as is the case for zfs-kmod), or included in the > FILESDIR, or they can be generated by the eclass from the modlist. > > This auto-generation option is just for convenience. The modlist already > contains all the information we need to define the dkms.conf, so all we > have to do is make the translation. Doing so makes it very easy for the > package maintainer to add dkms compatibility without actually writing a > custom dkms.conf. > > If you wish to drop the modlist method from linux-mod-r1 then you can > still do so. It just requires that when upgrading from EAPI 8 to 9 we > also port the ebuild to so other method of providing the dkms.conf (for > example putting a stub dkms.conf in FILESDIR, sed'ing in the PV, and > then putting it in the proper place). I might then want to adjust the > src_compile phase of the eclass a bit when bumping it to EAPI 9, but > again these are all easily solvable problems, and they are also > hypothetical problems. > > In the end this eclass does not really rely on the specifics of > linux-mod-r1 more then a consumer ebuild does. We rely on linux-mod-r1 > setting the MODULES_MAKEARGS, we rely on linux-mod-r1 to process the > modlist and set the default values there (I split this into a separate > function to avoid code duplication), and we rely on the > modules_process_dracut.conf.d function (again, just to avoid code > duplication). And that's it. Now I could drop the linux-mod-r1 commits > that split out this processing of the modlist and make the > modules_process_dracut.conf.d function public. But we gain nothing from > this since the ebuilds already rely on linux-mod-r1 doing what it does > in this area in exactly the same way that the eclass does, it only > results in some code duplication. > > Best regards, > Nowa > -- ionen
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