Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756918AbZGPBXZ (ORCPT ); Wed, 15 Jul 2009 21:23:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756885AbZGPBXX (ORCPT ); Wed, 15 Jul 2009 21:23:23 -0400 Received: from wa4ehsobe004.messaging.microsoft.com ([216.32.181.14]:21005 "EHLO WA4EHSOBE004.bigfish.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756884AbZGPBXW (ORCPT ); Wed, 15 Jul 2009 21:23:22 -0400 X-SpamScore: -18 X-BigFish: VPS-18(zz1432R98dN936eMzz1202hzzz32i6bh43j61h) X-Spam-TCS-SCL: 0:0 X-FB-SS: 5, X-WSS-ID: 0KMUP6H-03-GY3-01 Date: Thu, 16 Jul 2009 09:23:10 +0800 From: "Cai, Crane" To: ykzhao CC: Crane Cai , "lenb@kernel.org" , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] ACPI: add driver for SMBus Control Method Interface Message-ID: <20090716012310.GA5806@crane-desktop> Mail-Followup-To: "Cai, Crane" , ykzhao , "lenb@kernel.org" , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20090715060219.GA30514@crane-desktop> <1247651002.4113.9.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <1247651002.4113.9.camel@localhost.localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) X-OriginalArrivalTime: 16 Jul 2009 01:23:10.0345 (UTC) FILETIME=[FB187790:01CA05B3] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1731 Lines: 39 On Wed, Jul 15, 2009 at 05:43:22PM +0800, ykzhao wrote: > On Wed, 2009-07-15 at 14:02 +0800, Crane Cai wrote: >> This driver supports the SMBus Control Method Interface. It needs BIOS declare >> ACPI control methods via SMBus Control Method Interface Spec. > It seems that SM bus control is realized in BIOS. And OS can use the > given control method interface to access it. > Will this controller be accessed directly directly BIOS? Controller accessed by ACPI control method, the control method is called by OS. > If it can be accessed by BIOS, how to resolve the conflict between BIOS > and OS? About conflicts see next question's answer. > > In fact we see the conflict on some boxes. The SMbus controller will be > accessed by BIOS. If the corresponding driver is loaded for the SMBUS > controller, there exists the potential risk. In such case we will hide > the SMbus controller or not load the device driver for it. About conflicts, CMI driver access SMBus host controller via ACPI control methods. Its related resource will be declared in ACPI region. Its controll methods will be insured by BIOS. Native PCI interface SMBus host controller driver such as i2c-piix4.c, its resource is in PCI region. Its access methods is in its driver. So, CMI driver & native PCI interface driver use different resouces and methods to access SMBus host controller. 2 different devices controlled by 2 different drivers and no conflicts exists. > > Thanks. -- Best Regards, - Crane -- 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/