From owner-freebsd-acpi@FreeBSD.ORG Fri Feb 5 05:53:41 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 5FFF9106566B for ; Fri, 5 Feb 2010 05:53:41 +0000 (UTC) (envelope-from nate@root.org) Received: from mail.root.org (root.org [208.72.84.34]) by mx1.freebsd.org (Postfix) with ESMTP id 406C68FC0A for ; Fri, 5 Feb 2010 05:53:41 +0000 (UTC) Received: from [10.0.5.50] (ppp-71-139-29-85.dsl.snfc21.pacbell.net [71.139.29.85]) by mail.root.org (Postfix) with ESMTP id 84D584E04; Fri, 5 Feb 2010 05:53:39 +0000 (UTC) Message-ID: <4B6BB263.4040604@root.org> Date: Thu, 04 Feb 2010 21:53:39 -0800 From: Nate Lawson User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Andriy Gapon References: <4B6B4A3C.5090308@icyb.net.ua> In-Reply-To: <4B6B4A3C.5090308@icyb.net.ua> X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: freebsd-acpi@FreeBSD.org Subject: Re: acpi_ec_ecdt_probe => acpi_ec_identify 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: Fri, 05 Feb 2010 05:53:41 -0000 Andriy Gapon wrote: > I would like to convert acpi_ec_ecdt_probe to device_identify method. > Rationale: > 1. It doesn't look like any device is using acpi_ec's services during identify > stage (or earlier) and acpi_ec already has a rather high priority among acpi > drivers that it would probe and attach before most of them. > 2. Making a driver 'less special' is always a good thing in general. > 3. Probing/attachment of acpi_ec at the current very early stage may even fail > because it could be dependent on things done by other, even more fundamental, > drivers that provide system resources. > 4. To expand the above: on some systems EC _REG method accesses things that only > get dynamically loaded after Processor's _PDC/_OSC is evaluated[*]. Converting > acpi_ec_ecdt_probe => acpi_ec_identify won't help here, but this would be a > first step towards a solution. > > [*] > http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/142561 > Followups from Jan 15 on. I agree in concept. The ECDT-based probe method was intended to get it active as early as possible, and Linux has a quirk to create a fake ECDT to get an early EC on some systems that require it but don't have an ECDT. However, I thought jhb@'s multi-pass probe work would be a better way to support this than moving it into device_identify(). Is that code ready to use yet? -- Nate