Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756567Ab2BCOEq (ORCPT ); Fri, 3 Feb 2012 09:04:46 -0500 Received: from na3sys009aog124.obsmtp.com ([74.125.149.151]:57872 "EHLO na3sys009aog124.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756541Ab2BCOEo (ORCPT ); Fri, 3 Feb 2012 09:04:44 -0500 MIME-Version: 1.0 In-Reply-To: <1328228079-20716-1-git-send-email-venki@google.com> References: <1328227065-22045-1-git-send-email-venki@google.com> <1328228079-20716-1-git-send-email-venki@google.com> Date: Fri, 3 Feb 2012 15:04:43 +0100 Message-ID: Subject: Re: [PATCH] CPU C-state breakage with PM Qos change From: "Pihet-XID, Jean" To: Venkatesh Pallipadi , "Rafael J. Wysocki" , markgross Cc: Kevin Hilman , linux-kernel@vger.kernel.org, Len Brown , Linux PM mailing list Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1354 Lines: 32 Looping in linux-pm On Fri, Feb 3, 2012 at 1:14 AM, Venkatesh Pallipadi wrote: > Looks like change "PM QoS: Move and rename the implementation files" > made pm_qos depend on CONFIG_PM which depends on > PM_SLEEP || PM_RUNTIME > > That breaks CPU C-states with kernels not having these CONFIGs, causing CPUs > to spend time in Polling loop idle instead of going into deep C-states, > consuming way way more power. This is with either acpi idle or intel idle > enabled. > > Either CONFIG_PM should be enabled with any pm_qos users or > the !CONFIG_PM pm_qos_request() should return sane defaults not to break > the existing users. Here's is the patch for the latter option. I think the real question is whether PM QoS should be functional in all cases (as is ACPI) or whether only if certain options are set (CONFIG_PM). In the current code if CONFIG_PM is not enabled, a dummy PM QoS API is provided as function stubs in order for the build to succeed. Rafael, Mark, What do you think? Should PM QoS be enabled in all cases? Are there any known dependencies with CONFIG_PM? Regards, Jean -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/