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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 BABCAC47404 for ; Wed, 9 Oct 2019 14:13:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 939C3218AC for ; Wed, 9 Oct 2019 14:13:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729644AbfJIONQ (ORCPT ); Wed, 9 Oct 2019 10:13:16 -0400 Received: from eddie.linux-mips.org ([148.251.95.138]:38418 "EHLO cvs.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727769AbfJIONM (ORCPT ); Wed, 9 Oct 2019 10:13:12 -0400 Received: (from localhost user: 'macro', uid#1010) by eddie.linux-mips.org with ESMTP id S23993660AbfJIONJq54nj (ORCPT ); Wed, 9 Oct 2019 16:13:09 +0200 Date: Wed, 9 Oct 2019 15:13:09 +0100 (BST) From: "Maciej W. Rozycki" To: Paul Burton cc: "linux-mips@vger.kernel.org" , Paul Burton Subject: Re: [PATCH 1/4] MIPS: cmdline: Remove CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND In-Reply-To: Message-ID: References: <20191007221951.1889661-1-paul.burton@mips.com> User-Agent: Alpine 2.21 (LFD 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Wed, 9 Oct 2019, Maciej W. Rozycki wrote: > > CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND is not selected by any of our > > defconfigs, so remove it to simplify the messy command line logic in > > arch_mem_init() a little. > > That sounds like a poor argument for a functional regression to me. I > have the option enabled in several configs I have been using just to be > able to temporarily override any built-in parameters with ones typed from > the console monitor's prompt. Is it my mistake that I haven't put it in a > defconfig? Elaborating, there's IMO little sense to set MIPS_CMDLINE_BUILTIN_EXTEND in a defconfig, because there's usually no default command line to set there in the first place, as this will be installation-specific. Ergo I highly doubt the absence of the setting across the board is due to nobody (except for myself) using it. Therefore: Nacked-by: Maciej W. Rozycki NB DECstation systems use a DS1287 or a similar RTC/NVRAM chip to hold configuration and space is limited there. Up to 37 of kernel command line characters can be permanently stored, fewer on some systems, and used for automatic boot. Conversely when typed at the console monitor prompt there is no (known to me) limitation as to the length of the kernel command line requested. Therefore a kernel configured for those systems will normally have several parameters embedded within itself while letting the non-volatile storage or user input extend and/or selectively override them, e.g. for a different root device or whatever. However, as I noted above, there's no reasonable universal default command line to use with a defconfig, just as you could not come up with one for say an x86 PC. I hope this clarifies the matter. Maciej