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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 8FD17C6778A for ; Thu, 5 Jul 2018 21:54:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34A6124075 for ; Thu, 5 Jul 2018 21:54:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 34A6124075 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753526AbeGEVyV (ORCPT ); Thu, 5 Jul 2018 17:54:21 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58734 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753439AbeGEVyU (ORCPT ); Thu, 5 Jul 2018 17:54:20 -0400 Received: from localhost.localdomain (c-24-4-125-7.hsd1.ca.comcast.net [24.4.125.7]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 9CA62E50; Thu, 5 Jul 2018 21:54:19 +0000 (UTC) Date: Thu, 5 Jul 2018 14:54:18 -0700 From: Andrew Morton To: "Tian, Baofeng" Cc: "andrew.smirnov@gmail.com" , "linux-kernel@vger.kernel.org" , "Zhuang, Qihua" Subject: Re: [PATCH] reboot: add reboot_panic parameter Message-Id: <20180705145418.67fbcebca351c2d1142f3475@linux-foundation.org> In-Reply-To: References: <0038B620BAC72941BCBF48AEB892976C02CADD8C@shsmsx102.ccr.corp.intel.com> <20180702143057.1ca20a97ddfb91056010cec8@linux-foundation.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 5 Jul 2018 06:47:37 +0000 "Tian, Baofeng" wrote: > -----Original Message----- > From: Andrew Morton [mailto:akpm@linux-foundation.org] > Sent: Tuesday, July 3, 2018 5:31 AM > To: Tian, Baofeng > Cc: andrew.smirnov@gmail.com; linux-kernel@vger.kernel.org; Zhuang, Qihua > Subject: Re: [PATCH] reboot: add reboot_panic parameter > > On Mon, 2 Jul 2018 02:20:59 +0000 "Tian, Baofeng" wrote: > > > This "reboot_panic" kernel cmdline parameter allow to change the > > reboot mode in case of panic only. It use the same format as the > > "reboot" parameter. > > Example, for cf9 warm reset in case of panic: reboot_panic=p,w > > currently it only support cold/warm reset in case of panic. > > Why should we do this? What are the benefits, what are the usecases, etc? > > Some user-facing documentation should clear that up. `grep -r reboot= Documentation' will direct you to the appropriate places. > (top-posting repaired. Please don't top-post) > Hi, Morton "Andrew" :) > On android platform, if use adb reboot, it will automatically reboot with cold reset. > cold reset will reset RAM and cause RAM lose data information, if we want to enable some debug features > like pstore, and ramdump etc, warm reset is needed to keep RAM across reset > > So, we add this interface to allow people to set reboot as warm to get log data across reset. > OK, sounds good. Please add this info to the changelog, add the user documentation and resend.