From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH 07/15] ARM: cpuidle: add init/exit routine Date: Mon, 25 Mar 2013 20:46:09 +0100 Message-ID: <5150A981.1090001@linaro.org> References: <1364234140-514-1-git-send-email-daniel.lezcano@linaro.org> <1364234140-514-8-git-send-email-daniel.lezcano@linaro.org> <20130325181038.GA631@lunn.ch> <51509873.1010408@linaro.org> <20130325190908.GC631@lunn.ch> <5150A378.60608@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-we0-f173.google.com ([74.125.82.173]:35901 "EHLO mail-we0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932858Ab3CYTqJ (ORCPT ); Mon, 25 Mar 2013 15:46:09 -0400 Received: by mail-we0-f173.google.com with SMTP id t57so1271388wey.32 for ; Mon, 25 Mar 2013 12:46:08 -0700 (PDT) In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Amit Kucheria Cc: Nicolas Pitre , Andrew Lunn , Lists linaro-kernel , Magnus Damm , ben-linux@fluff.org, linux-pm@vger.kernel.org, "Nori, Sekhar" , Patch Tracking , Rob Herring , Russell King - ARM Linux , "Rafael J. Wysocki" , Kevin Hilman , horms@verge.net.au, jason@lakedaemon.net, kernel@pengutronix.de, Kukjin Kim , plagnioj@jcrosoft.com, linux@maxim.org.za, Lists LAKML , Len Brown On 03/25/2013 08:31 PM, Amit Kucheria wrote: > On Tue, Mar 26, 2013 at 12:50 AM, Daniel Lezcano > wrote: >> On 03/25/2013 08:09 PM, Andrew Lunn wrote: >>>>> Please could you add a comment in the code about which piece is >>>>> specific to ARM, because its not obvious to me. Its not like ther= e is >>>>> a reference to WFI for example. It looks like this code could go = in >>>>> drivers/cpuidle/cpuidle.c >>>> >>>> Yes, I agree. At the first glance, the code, as it is, could go in= this >>>> file but more ARM specific code will be moved to this ARM generic = code >>>> driver like device tree description and couple idle states. The in= it >>>> function would be more arch specific then. >>> >>> Hi Daniel >>> >>> There was a discussion about device tree bindings when i posted >>> the kirkwood cpuidle driver, now in drivers/cpuidle/cpuidle-kirkwoo= d.c. >>> >>> The conclusion was that pseudo devices, like cpuidle, do not have D= T >>> bindings. They can check of_machine_is_compatible(), like >>> cpuidle-calxeda.c does, or they are platform drivers, which is what >>> cpuidle-kirkwood.c is. >>> >>> Even if DT binding was allowed, it again should not be ARM specific= =2E >> >> If the DT binding was allowed, I *may* not be ARM specific but will >> certainly used only by the ARM drivers as the x86 platform uses ACPI= or >> static tables. >> >>> Are coupled idle states ARM specific? >> >> Well the code is not arch specific but today the idle coupling is AR= M >> specific because it is the only arch using this kind of synchronizat= ion. >> There is also a last man standing algorithm common to ux500 and imx >> (maybe exynos soon) I would like to merge into this ARM driver. >=20 > Nico has developed a last man standing algorithm[1] for big.LITTLE > TC2. That too needs to be considered during this consolidation. While > it was developed for multi-cluster configurations, I don't see what i= t > shouldn't work here too. >=20 > [1] http://lwn.net/Articles/539082/ I had it in mind when answering but I didn't mention it. Thanks Amit for the pointer. -- Daniel --=20 Linaro.org =E2=94=82 Open source software for= ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog