From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756954AbcGGIk3 (ORCPT ); Thu, 7 Jul 2016 04:40:29 -0400 Received: from foss.arm.com ([217.140.101.70]:34588 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752207AbcGGIk1 (ORCPT ); Thu, 7 Jul 2016 04:40:27 -0400 Message-ID: <577E14F6.6060706@arm.com> Date: Thu, 07 Jul 2016 09:38:14 +0100 From: James Morse User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.6.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" , Chen Yu CC: linux-pm@vger.kernel.org, Thomas Gleixner , "H. Peter Anvin" , Pavel Machek , Borislav Petkov , Peter Zijlstra , Ingo Molnar , Len Brown , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][RFC v3] x86, hotplug: Use hlt instead of mwait if invoked from disable_nonboot_cpus References: <1467105403-5085-1-git-send-email-yu.c.chen@intel.com> <209704957.TWElLMTLfP@vostro.rjw.lan> In-Reply-To: <209704957.TWElLMTLfP@vostro.rjw.lan> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rafael, On 07/07/16 01:33, Rafael J. Wysocki wrote: > Below is my sort of version of this (untested) and I did it this way, because > the issue is specific to resume from hibernation (the workaround need not be > applied anywhere else) and the hibernate_resume_nonboot_cpu_disable() thing may > be useful to arm64 too if I'm not mistaken (James?). Yes, we will always need to do something extra (based on data in the arch_hibernation_header) to resume if CPU0 was offline, or kexec meant we no longer know which CPU the firmware will boot us on. > Actually, if arm64 uses it too, the __weak implementation can be dropped, > because it will be possible to make it depend on ARCH_HIBERNATION_HEADER > (x86 and arm64 are the only users of that). Heh, I avoided that as it felt too much like a hack! Thanks, James