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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 0D7C3C43219 for ; Wed, 1 May 2019 09:50:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D0EBD21743 for ; Wed, 1 May 2019 09:50:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726326AbfEAJuC (ORCPT ); Wed, 1 May 2019 05:50:02 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:57378 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726052AbfEAJuC (ORCPT ); Wed, 1 May 2019 05:50:02 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8BDAFA78; Wed, 1 May 2019 02:50:01 -0700 (PDT) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CE70D3F719; Wed, 1 May 2019 02:49:59 -0700 (PDT) Date: Wed, 1 May 2019 10:49:53 +0100 From: Sudeep Holla To: Sodagudi Prasad Cc: julien.thierry@arm.com, will.deacon@arm.com, catalin.marinas@arm.com, mark.rutland@arm.com, lorenzo.pieralisi@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sudeep Holla Subject: Re: PSCI version 1.1 and SYSTEM_RESET2 Message-ID: <20190501094953.GA21851@e107155-lin> References: <24970f7101952f347bd4046c9a980473@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 30, 2019 at 05:07:31PM -0700, Sodagudi Prasad wrote: > On 2019-04-30 14:44, Sodagudi Prasad wrote: > +Sudeep > > > Hi Mark/Will, > > > > I would like to understand whether ARM linux community have plans to > > support PSCI version 1.1 or not. > > PSCI_1_1 specification introduced support for SYSTEM_RESET2 command > > and this new command helps mobile devices to SYSTEM_WARM_RESET > > support. Rebooting devices with warm reboot helps to capture the > > snapshot of the ram contents for post-mortem analysis. > > I think, there is a recent discussion from Sudeep for the SYSTEM_RESET2 > support. > https://patchwork.kernel.org/patch/10884345/ > This has landed in -next, and hopefully must appear in v5.2 > > Hi Sudeep, > > I was going through your discussion in the below list - > https://lore.kernel.org/lkml/d73d3580-4ec1-a281-4585-5c776fc08c79@xilinx.com/ > > There is no provision to set up reboot mode dynamically instead kernel > command line parameter. > Looking for options to reboot device with warm reboot option when kernel > crashed. > > panic() --> emergency_restart() --> machine_emergency_restart() --> > machine_restart(NULL); > > It would nice if there is a config option to reboot the device either in > warm or cold in the case of kernel panic. I presume you prefer to do warm boot in case of panic to get a dump of the memory to inspect ? If so, is kexec/kdump not the mechanism to achieve that ? I am just trying to understand the use case. Xilinx asked for the same but never got to understand their use case. -- Regards, Sudeep