From owner-freebsd-acpi@FreeBSD.ORG Mon Sep 13 17:07:44 2010 Return-Path: Delivered-To: freebsd-acpi@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C118F106566B; Mon, 13 Sep 2010 17:07:44 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id A07968FC19; Mon, 13 Sep 2010 17:07:43 +0000 (UTC) Received: from odyssey.starpoint.kiev.ua (alpha-e.starpoint.kiev.ua [212.40.38.101]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id UAA23459; Mon, 13 Sep 2010 20:07:42 +0300 (EEST) (envelope-from avg@icyb.net.ua) Message-ID: <4C8E5A5D.6000303@icyb.net.ua> Date: Mon, 13 Sep 2010 20:07:41 +0300 From: Andriy Gapon User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.2.9) Gecko/20100909 Lightning/1.0b2 Thunderbird/3.1.3 MIME-Version: 1.0 To: Alexander Motin References: <4C8BCAC5.5050008@root.org> <4C8C8B64.8020907@FreeBSD.org> <20100912182625.c49d3f1d.nork@FreeBSD.org> <4C8C9F06.4090505@icyb.net.ua> <20100912190537.621e357e.nork@FreeBSD.org> <20100912190952.8c0d5726.nork@FreeBSD.org> <20100912192518.e791c191.nork@FreeBSD.org> <4C8CAC01.70004@icyb.net.ua> <4C8CAD7D.50602@FreeBSD.org> <4C8CF03F.1050902@icyb.net.ua> <4C8CF412.9080601@icyb.net.ua> <4C8CF91A.4040804@FreeBSD.org> In-Reply-To: <4C8CF91A.4040804@FreeBSD.org> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-acpi@FreeBSD.org, Norikatsu Shigemura Subject: Re: CPU C-state storange on Panasonic TOUGH BOOK CF-R9 X-BeenThere: freebsd-acpi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ACPI and power management development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Sep 2010 17:07:44 -0000 on 12/09/2010 19:00 Alexander Motin said the following: > > I am not sure this patch is complete: Well, I agree, it's far from complete. And situation is somewhat messy. > 1) AFAIR I have seen somewhere example where system had several C-states > with different latency, but the same type - C3. Type only means > enter/exit semantics, and there could be several states with the same > semantics. Not sire how to properly them in this case. ACPI specification suggests how to address this, but I am not sure if we want to follow that suggestion and how we would do that: ACPI> Notice in the example above that OSPM should anticipate the possibility of a _CST object providing more ACPI> than one entry with the same C_State_Type value. In this case OSPM must decide which C_State_Register ACPI> it will use to enter that C state. So it looks like the specification does tie C_State_Type to "C state". But then, in general, the specification looks confusing. It mentions C4, ..., Cn states; but then says that their enter/exit semantics should correspond to C1, C2, C3; but then it uses "1, 2, 3, *etc*" [emphasis mine] when it describes C State type. So, at least I am confused as to what they would designate with C4 - a state described in _CST with type of 4, or a forth state in _CST perhaps with a type of 3. And entry/exit semantics the state would have in the former case. I do not see an explicit answer in their wording. > May be existing > approach was not so bad. It is ACPI C-states, not CPU C-states, they are > not same. > May be we should just mention type somewhere in addition. > 2) This change makes heavily understandable values of cx_lowest. > 3) If touch cx_lowest, I would prefer to see there possibility to set it > to some abstract C6 or whatever, allowing system automatically choose > state it has available at the moment. > Yes, I agree. It's just overall confusing. But you are correct that index of a C-state works better than "C-state-type" or whatever it can be called. And a user probably doesn't care much about the latter. But probably it's a good idea to report the type somewhere. I am also going to take a look how Linux and OpenSolaris name the C-states. -- Andriy Gapon