Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754047AbaFKEwN (ORCPT ); Wed, 11 Jun 2014 00:52:13 -0400 Received: from mail-oa0-f44.google.com ([209.85.219.44]:47040 "EHLO mail-oa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750995AbaFKEwL (ORCPT ); Wed, 11 Jun 2014 00:52:11 -0400 MIME-Version: 1.0 In-Reply-To: References: <1402090985-8061-1-git-send-email-dianders@chromium.org> <20140607181221.GB25068@e102568-lin.cambridge.arm.com> <20140609223831.GB16889@e102568-lin.cambridge.arm.com> Date: Wed, 11 Jun 2014 10:22:10 +0530 X-Google-Sender-Auth: puFF40SPA9Iu9VQsGlAULxvP_mE Message-ID: Subject: Re: [PATCH] ARM: EXYNOS: mcpm: Don't rely on firmware's secondary_cpu_start From: Chander Kashyap To: Nicolas Pitre Cc: Doug Anderson , "linux-arm-kernel@lists.infradead.org" , Kukjin Kim , "linux@arm.linux.org.uk" , Kevin Hilman , Andrew Bresticker , Inderpal Singh , "linux-kernel@vger.kernel.org" , Chander Kashyap , "olof@lixom.net" , Tushar Behera , Lorenzo Pieralisi , Thomas Abraham , Abhilash Kesavan , Javier Martinez Canillas , "linux-samsung-soc@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Doug, On Tue, Jun 10, 2014 at 9:19 PM, Nicolas Pitre wrote: > On Tue, 10 Jun 2014, Doug Anderson wrote: > >> My S-state knowledge is not strong, but I believe that Lorenzo's >> questions matter if we're using S2 for CPUidle (where we actually turn >> off power and hot unplug CPUs) but not when we're using S1 for CPUidle >> (where we just enter WFI/WFE). >> No Its not plain WFI. All cores in Exynos5420 can be powered off independently. This functionality has been tested. Below is the link for the posted patches. https://lkml.org/lkml/2014/6/10/194 And as Nicolas wrote, these patches need MCPM for that. >> I believe that in ChromeOS we use S1 CPUidle and that it works fine. >> We've never implemented S2 that I'm aware of. > > You'll have to rely on MCPM for that. That's probably why it hasn't > been implemented before. > > > Nicolas > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- 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/