From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54706C433DB for ; Wed, 13 Jan 2021 11:03:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2574224B0 for ; Wed, 13 Jan 2021 11:03:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727329AbhAMLDb (ORCPT ); Wed, 13 Jan 2021 06:03:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:40238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727245AbhAMLD3 (ORCPT ); Wed, 13 Jan 2021 06:03:29 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5C91A233A2 for ; Wed, 13 Jan 2021 11:02:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610535768; bh=XWUiSn4NUR3he8EUTvIP/v7uvWBzmVhRoEdWjHB6zhc=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=MGatXpaQfo/Y8zXaxcR27lvn62WSWF9ORnHYTo7TD2o809O+6QI2E8+ejU2iKrBFT /meeLz0+B5wtgkSEh1M/AGIos+BlwMO/6po3LKOw28ev5LqdX/u94xIto96qCM5BtH 49gz5L0nni3/+LForSxuH3NnpKVmLoT2Lo8n8eBkfkf+LDfblr/l2jfoh61Yp994qC zlLU7LbRrjbtTxjNORU6jVwawXgsr/AJ4RG5C46CxwDCy+7A2gc2cdIr1Um5i3F7ia 03WckDbNmREUoDzfLNuEtUsOavFTnGBBkIjWROORKmiZ+uRA/4bXCqmNVDgNL6E5t0 zSxX550bBEgiQ== Received: by mail-oi1-f179.google.com with SMTP id q205so1600644oig.13 for ; Wed, 13 Jan 2021 03:02:48 -0800 (PST) X-Gm-Message-State: AOAM533SflTUN1Bg4b1+768oDWFLv2E0FD9KVkV1UZMO/Y7vgROwG6pO aYVAKsXBfk6J7N+VbIKtKFBB+8ucby2IpuAwtS0= X-Google-Smtp-Source: ABdhPJxw4S7HJq3mnBPCwf2+3LbnfN8YuFlvLRpS4q2XmGr7wCe5FtKI7ZJNHpPG1jMT7wyRz2WCpbzRy68uaaHSGQ0= X-Received: by 2002:aca:44d:: with SMTP id 74mr823032oie.4.1610535767494; Wed, 13 Jan 2021 03:02:47 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Arnd Bergmann Date: Wed, 13 Jan 2021 12:02:29 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: Old platforms: bring out your dead To: Andy Shevchenko Cc: Linux ARM , Linux Kernel Mailing List , Krzysztof Adamski , Oleksij Rempel , Baruch Siach , Russell King - ARM Linux , Daniel Tang , =?UTF-8?Q?Uwe_Kleine=2DK=C3=B6nig?= , Jamie Iles , Barry Song , Viresh Kumar , Linus Walleij , Jonas Jensen , Marc Gonzalez , Hartley Sweeten , Lubomir Rintel , Neil Armstrong , Shawn Guo , Alex Elder , Alexander Shiyan , Koen Vandeputte , Hans Ulli Kroll , Vladimir Zapolskiy , Wei Xu , Steven Rostedt , Yoshinori Sato , Mark Salter , Michael Ellerman , Geert Uytterhoeven , Thomas Bogendoerfer Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 13, 2021 at 11:31 AM Andy Shevchenko wrote: > > On Sat, Jan 9, 2021 at 12:58 AM Arnd Bergmann 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