From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72ECFC33CAF for ; Fri, 17 Jan 2020 01:55:59 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 45D9D2072B for ; Fri, 17 Jan 2020 01:55:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 45D9D2072B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:51230 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1isGre-0007jb-Ge for qemu-devel@archiver.kernel.org; Thu, 16 Jan 2020 20:55:58 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46635) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1isGr1-00078d-Bh for qemu-devel@nongnu.org; Thu, 16 Jan 2020 20:55:20 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1isGqz-00071l-Lp for qemu-devel@nongnu.org; Thu, 16 Jan 2020 20:55:19 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:2736 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1isGqw-0006qE-EE; Thu, 16 Jan 2020 20:55:14 -0500 Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 3BDB247A1078ECE07340; Fri, 17 Jan 2020 09:55:09 +0800 (CST) Received: from [127.0.0.1] (10.133.216.73) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.439.0; Fri, 17 Jan 2020 09:55:00 +0800 Subject: Re: [PATCH 2/2] arm/virt/acpi: remove _ADR from devices identified by _HID To: Igor Mammedov References: <20191219064759.35053-1-guoheyi@huawei.com> <20191219064759.35053-3-guoheyi@huawei.com> <20200105072504-mutt-send-email-mst@kernel.org> <20200105074308-mutt-send-email-mst@kernel.org> <20200116142508.1d82af31@redhat.com> From: Guoheyi Message-ID: Date: Fri, 17 Jan 2020 09:54:58 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20200116142508.1d82af31@redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed X-Originating-IP: [10.133.216.73] X-CFilter-Loop: Reflected Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 45.249.212.191 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Shannon Zhao , qemu-arm@nongnu.org, Corey Minyard , wanghaibin.wang@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" =E5=9C=A8 2020/1/16 21:25, Igor Mammedov =E5=86=99=E9=81=93: > On Thu, 16 Jan 2020 19:56:19 +0800 > Guoheyi wrote: > >> =E5=9C=A8 2020/1/5 20:53, Michael S. Tsirkin =E5=86=99=E9=81=93: >>> On Sun, Jan 05, 2020 at 07:34:01AM -0500, Michael S. Tsirkin wrote: >>>> On Thu, Dec 19, 2019 at 02:47:59PM +0800, Heyi Guo wrote: >>>>> According to ACPI spec, _ADR should be used for device which is on = a >>>>> bus that has a standard enumeration algorithm. It does not make sen= se >>>>> to have a _ADR object for devices which already have _HID and will = be >>>>> enumerated by OSPM. >>>>> >>>>> Signed-off-by: Heyi Guo >>>> Are you sure? I would think this depends on the ID and the device >>>> really. E.g. PCI devices all are expected to have _ADR and some of t= hem >>>> have a _HID. >>> To clarify I am not commenting on patches. >>> The spec says this: >>> 6.1.5 _HID (Hardware ID) >>> >>> This object is used to supply OSPM with the device=E2=80=99s PNP ID = or ACPI ID. 1 >>> >>> When describing a platform, use of any _HID objects is optional. How= ever, a _HID object must be >>> >>> used to describe any device that will be enumerated by OSPM. OSPM on= ly enumerates a device >>> >>> when no bus enumerator can detect the device ID. For example, device= s on an ISA bus are >>> >>> enumerated by OSPM. Use the _ADR object to describe devices enumerat= ed by bus enumerators >>> >>> other than OSPM. >>> >>> >>> Note: "detect the device ID" not "enumerate the device" which I think >>> means there's a driver matching this vendor/device ID. >>> >>> So it seems fine to have _ADR so device is enumerated, and still have >>> _HID e.g. so ACPI driver can be loaded as fallback if there's >>> no bus driver. >>> >>> >>> Note I am not saying the patch itself is not correct. >>> Maybe these devices are not on any standard bus and that >>> is why they should not have _ADR? I have not looked. >>> >>> I am just saying that spec does not seem to imply _HID and _ADR >>> can't coexist. >> More reading on the spec, I found a statement as below >> (https://uefi.org/sites/default/files/resources/ACPI_6_3_May16.pdf, >> section 6.1, on top of page 343): > I'd replace 'It does not make sense ...' sentence with pointer to spec > and quote below in commit message. Sure; actually I hadn't found this statement in the spec when making the=20 patch :) Thanks, Heyi > >> A device object must contain either an _HID object or an _ADR object, >> but should not contain both > [...] > > > .