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=-7.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 A1C55C433DF for ; Fri, 21 Aug 2020 07:30:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7ED8420702 for ; Fri, 21 Aug 2020 07:30:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727945AbgHUHa2 (ORCPT ); Fri, 21 Aug 2020 03:30:28 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2679 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726864AbgHUHa1 (ORCPT ); Fri, 21 Aug 2020 03:30:27 -0400 Received: from lhreml724-chm.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id 484C6D3BA6AE77980649; Fri, 21 Aug 2020 08:30:26 +0100 (IST) Received: from [127.0.0.1] (10.47.8.200) 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 15.1.1913.5; Fri, 21 Aug 2020 08:30:25 +0100 From: John Garry Subject: Re: v5.9-rc1 commit reliably breaks pci nvme detection To: Christoph Hellwig , Jens Axboe CC: Sagi Grimberg , Chaitanya Kulkarni , , , "Ahmed S. Darwish" , Keith Busch References: <20200817135011.GA2072@lx-t490> <20200817155658.GB1221871@dhcp-10-100-145-180.wdl.wdc.com> <2356f514-9408-6a6f-871d-046984963533@kernel.dk> <20200820170729.GA4116@lx-t490> <83a3d1b6-1eb5-859b-3c5c-287d8d18a99b@kernel.dk> <20200820171214.GA15207@infradead.org> Message-ID: Date: Fri, 21 Aug 2020 08:28:03 +0100 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: <20200820171214.GA15207@infradead.org> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.8.200] X-ClientProxiedBy: lhreml728-chm.china.huawei.com (10.201.108.79) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/08/2020 18:12, Christoph Hellwig wrote: > On Thu, Aug 20, 2020 at 11:10:58AM -0600, Jens Axboe wrote: >> To be fair, I've only heard this one complaint about it, so hopefully it's >> not too widespread. I'm on an x86-64 laptop myself with nvme, and it works >> just fine:-) > The cause for this is the weird NVMe of by ones, where 0 in a field > means 1. I thought that this was a common trick by spec writers to fit a number in range (0, 2^x] in x bits (as opposed to x+1).