From mboxrd@z Thu Jan 1 00:00:00 1970 From: Preeti U Murthy Subject: Re: [PATCH] cpufreq: powernv: Register the driver with reboot notifier Date: Fri, 22 Aug 2014 08:18:06 +0530 Message-ID: <53F6AF66.10204@linux.vnet.ibm.com> References: <1408015178-21745-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> <53F57E51.4060200@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from e35.co.us.ibm.com ([32.97.110.153]:50261 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755553AbaHVCsP (ORCPT ); Thu, 21 Aug 2014 22:48:15 -0400 Received: from /spool/local by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 21 Aug 2014 20:48:15 -0600 In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Viresh Kumar , Shilpasri G Bhat Cc: "linux-pm@vger.kernel.org" , "Rafael J. Wysocki" , Linux Kernel Mailing List , Shilpasri G Bhat , "linuxppc-dev@lists.ozlabs.org" Hi Viresh, On 08/21/2014 11:56 AM, Viresh Kumar wrote: > On 21 August 2014 10:36, Shilpasri G Bhat wrote: >> The intention here is stop the cpufreq governor and then to set the cpus to >> nominal frequency so as to ensure that the frequency won't be changed later. >> >> The .suspend callback of the driver is not called during reboot/kexec. >> So we need an explicit reboot notifier to call cpufreq-suspend() to >> suffice the requirement. > > Hi Shilpa, > > No, we can't allow any platform driver to misuse cpufreq_suspend(). > Platform drivers aren't *allowed* to call this routine. At the moment this looks like the best way forward. We need to do this cleanly by ensuring that we stop the governors and then call into the driver to deal with the cpu frequency in its own way during reboot. The best way to do this would be by calling this routine. Either this or cpufreq_suspend() should be called in the reboot path generically. The latter might not be an enticing option for other platforms. Regards Preeti U Murthy > > Now the deal is how do we move to nominal frequency on reboot.. > @Rafael: Any suggestions? How do we ensure that governors > are stopped on these notifiers, or if there is some other solution here? > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev >