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=-5.6 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 39034C433E0 for ; Sat, 27 Feb 2021 03:39:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E46264F17 for ; Sat, 27 Feb 2021 03:39:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230019AbhB0DjI (ORCPT ); Fri, 26 Feb 2021 22:39:08 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:13094 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229864AbhB0DjA (ORCPT ); Fri, 26 Feb 2021 22:39:00 -0500 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DnXJ62KfGz16C83; Sat, 27 Feb 2021 11:36:38 +0800 (CST) Received: from [10.67.102.118] (10.67.102.118) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.498.0; Sat, 27 Feb 2021 11:38:08 +0800 Subject: Re: [RFC PATCH] USB:XHCI:Modify XHCI driver for USB2.0 controller To: Alan Stern CC: , , , , References: <1614327697-1021-1-git-send-email-liulongfang@huawei.com> <20210226163004.GB1392547@rowland.harvard.edu> From: liulongfang Message-ID: Date: Sat, 27 Feb 2021 11:38:08 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20210226163004.GB1392547@rowland.harvard.edu> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.102.118] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/2/27 0:30, Alan Stern wrote: > On Fri, Feb 26, 2021 at 04:21:37PM +0800, Longfang Liu wrote: >> Our current XHCI hardware controller has been customized to only >> support USB 2.0 ports. When using the current xhci driver, an xhci >> controller device and an ehci controller device will be created >> automatically. > > That sentence makes no sense at all. An EHCI controller device is a > piece of hardware. How can an xHCI driver, which is a piece of > software, create a piece of hardware? > > Alan Stern > . > The hardware device is a complete USB3.0 controller, but I hope to support a USB2.0-only mode through software configuration. Thanks. Longfang Liu