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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5F016C33CB1 for ; Tue, 14 Jan 2020 09:47:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3EF7924677 for ; Tue, 14 Jan 2020 09:47:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728964AbgANJrK (ORCPT ); Tue, 14 Jan 2020 04:47:10 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2264 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725842AbgANJrJ (ORCPT ); Tue, 14 Jan 2020 04:47:09 -0500 Received: from LHREML713-CAH.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id 0524B413676FB742ABE3; Tue, 14 Jan 2020 09:47:08 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by LHREML713-CAH.china.huawei.com (10.201.108.36) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 14 Jan 2020 09:47:07 +0000 Received: from [127.0.0.1] (10.202.226.43) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 14 Jan 2020 09:47:07 +0000 Subject: Re: [PATCH v1] ACPI/IORT: Workaround for IORT ID count "minus one" issue To: Hanjun Guo , Lorenzo Pieralisi , Sudeep Holla , "Rafael J. Wysocki" , Pankaj Bansal CC: "linux-acpi@vger.kernel.org" , Linuxarm , "linux-arm-kernel@lists.infradead.org" References: <1577708824-4873-1-git-send-email-guohanjun@huawei.com> From: John Garry Message-ID: Date: Tue, 14 Jan 2020 09:47:06 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.202.226.43] X-ClientProxiedBy: lhreml729-chm.china.huawei.com (10.201.108.80) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On 14/01/2020 07:19, Hanjun Guo wrote: > On 2020/1/13 17:34, John Garry wrote: >> On 30/12/2019 12:27, Guohanjun (Hanjun Guo) wrote: >>> +}; >>> + >>> +static bool apply_id_count_workaround; >>> + >>> +static struct iort_workaround_oem_info wa_info[] __initdata = { >>> +    { >>> +        .oem_id        = "HISI  ", >>> +        .oem_table_id    = "HIP07   ", >>> +        .oem_revision    = 0, >>> +    }, { >>> +        .oem_id        = "HISI  ", >>> +        .oem_table_id    = "HIP08   ", >>> +        .oem_revision    = 0, >>> +    } >>> +}; >> >> Am I right in saying that any future BIOS for these chipsets will have to continue to have buggy firmware? If so, it's unfortunate. > > For better compatibility, I would say yes :( > > For example, if you fix that in the firmware, and update > the IORT revision number, then it will run pretty good > on new version of the kernel, but not on old version of > kernel without the backporting of this patch. ok, so that seems to be a trade off then. Having to backport introduces a risk. So then it might be good to add a comment to ID count members in open-source edk2-platforms hip07 and hip08 IORTs to mention it is buggy, so not to be copied as a reference. Cheers, John