From owner-svn-src-all@FreeBSD.ORG Mon Jul 2 17:41:03 2012 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 151791065675; Mon, 2 Jul 2012 17:41:03 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-bk0-f54.google.com (mail-bk0-f54.google.com [209.85.214.54]) by mx1.freebsd.org (Postfix) with ESMTP id 105F28FC26; Mon, 2 Jul 2012 17:41:01 +0000 (UTC) Received: by bkcje9 with SMTP id je9so435317bkc.13 for ; Mon, 02 Jul 2012 10:41:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=Lx8nwU3DHuvDd+xiOmJ9pHtxhCuD+P14fuCydJr9afk=; b=wjxwQR94TqYlrtlsfoZDYtY3Cf80L9jvx6vx64R/hjpj/YbVN2s1kHzBycL8fAbE+G muCIkLL0FwXF9yc2VQwS/zBl0roqwyIm/QP9jONicHJz1Xah+rnu5sAuDXK2eCYTj8JE u/GMLDQsbS8AFk5pQx0JelTCRgo1jy4A/YSdgrD8jMSIRaEt8DA3LOf6EBKHLMMSDu6a eK6bnE7i8SnzXcWA1aD2KXC9v9X3uoGeCEjkaGN6PO4iL3EBKOwz4cgmUwP/IhV8dGbS 3mGA7E5WInKGoHOuz3c3tA/1sywr0wy6b92O01GOkAhzaQlUtxH72I5p3nEg545j5Ipy cv0g== Received: by 10.205.136.3 with SMTP id ii3mr7964686bkc.101.1341250861073; Mon, 02 Jul 2012 10:41:01 -0700 (PDT) Received: from mavbook2.mavhome.dp.ua (pc.mavhome.dp.ua. [212.86.226.226]) by mx.google.com with ESMTPS id h18sm14439941bkh.8.2012.07.02.10.40.58 (version=SSLv3 cipher=OTHER); Mon, 02 Jul 2012 10:40:59 -0700 (PDT) Sender: Alexander Motin Message-ID: <4FF1DD29.1040003@FreeBSD.org> Date: Mon, 02 Jul 2012 20:40:57 +0300 From: Alexander Motin User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:13.0) Gecko/20120621 Thunderbird/13.0.1 MIME-Version: 1.0 To: Sean Bruno References: <201207021657.q62GvD7j082717@svn.freebsd.org> <4FF1D62C.2090705@FreeBSD.org> <1341250226.3342.6.camel@powernoodle.corp.yahoo.com> In-Reply-To: <1341250226.3342.6.camel@powernoodle.corp.yahoo.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "svn-src-head@FreeBSD.org" , Sean Bruno , "src-committers@FreeBSD.org" , "svn-src-all@FreeBSD.org" Subject: Re: svn commit: r238004 - in head: etc/rc.d sys/dev/acpica X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Jul 2012 17:41:03 -0000 On 07/02/12 20:30, Sean Bruno wrote: > On Mon, 2012-07-02 at 10:11 -0700, Alexander Motin wrote: >>> This didn't break anything but led to a display of: >>> * dev.cpu.0.cx_supported: C1/1 C2/96 >>> >>> Instead of >>> * dev.cpu.0.cx_supported: C1/1 C3/96 >>> >>> MFC after: 2 weeks >> >> If I remember correctly, ACPI spec directly specifies that there can >> be >> several C-states with the same type but with different enter method >> and >> exit latency. I have never seen any system with more then 3 C-states >> yet, but technically I think that is possible. Type field defines >> enter/exit semantics, respecting cache coherency and other things, so >> I >> think there can be more then one state with, for example, C3 >> semantics. >> Latest CPUs support states C1, C3 and C5, while ACPI AFAIK defines >> only >> three types and it may happen that both C3 and C5 have type-3 >> semantics. > > From my read of the current ACPI specs, there isn't anything past C3. Right. Because that type semantics is already quite strict to not need deeper. ACPI doesn't bother how CPU implements C3 and C5 and where it saves context. > However, Intel has definied Mwate Cstates that use the same nomenclature > and confuse what people think Cstates are. Is this what you mean by > "C5" Yes. ACPI C-states are not equal to CPU C-states and none of them are equal to ACPI types. I am not sure there is enough information to be more precise then we are now, unless we will hardcode it based on CPU IDs. ACPI spec allows BIOS to report how to enter state using MWAIT. In that case it would be possible to report it. But I haven't seen that used. -- Alexander Motin