| From | Arnd Bergmann <> | Date | Wed, 13 Jan 2021 12:02:29 +0100 | Subject | Re: Old platforms: bring out your dead |
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On Wed, Jan 13, 2021 at 11:31 AM Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > > On Sat, Jan 9, 2021 at 12:58 AM Arnd Bergmann <arnd@kernel.org> wrote: > > > > After v5.10 was officially declared an LTS kernel, > > I have a question here. Maybe I have missed something, but how LTS > helps in this case? LTS AFAIR has a rule "upstream first". How can you > provide a patch to be backported if there is no upstream for it > anymore?
Platform specific bugs are usually not the problem here, and if something does happen on deleted code, I would expect you can get an exception to the "upstream first" rule.
What I was getting at here were the things in the second category, the stuff that is is still maintained and working, but so old that it becomes a burden for maintainers. If a maintainer knows who all the users are and what they do with their machines, removing the platform from mainline would be a chance to get everyone to use the same LTS version so they can get bugfixes to common kernel code for a few more years and benefit from everyone else testing the same codebase.
> > * 80486SX/DX: 80386 CPUs were dropped in 2012, and there are > > indications that 486 have no users either on recent kernels. > > There is still the Vortex86 family of SoCs, and the oldest of those were > > 486SX-class, but all the modern ones are 586-class. > > * Alpha 2106x: First generation that lacks some of the later features. > > Since all Alphas are ancient by now, it's hard to tell whether these have > > any fewer users. > > We still have Intel Quark available. I run vanilla from time to time > on it due to the presence of peripherals I can't find elsewhere on x86 > boards.
While Quark is derived from a i486 pipeline, the kernel treats it as CONFIG_M586TSC, as it contains fpu, rdtsc, cpuid and cmpxchg8b instructions but no cmov or mmx. More importantly, you wouldn't find the vintage i486 peripherals (drivers/ide, drivers/video/fbdev, VLB, ISA, floppy) but instead have modern stuff like USB, PCIe, and eMMC.
Arnd
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