Received: by 2002:a05:6a10:8c0a:0:0:0:0 with SMTP id go10csp1347090pxb; Fri, 26 Feb 2021 08:32:10 -0800 (PST) X-Google-Smtp-Source: ABdhPJz17DRwF5Lx0LKRiS1JzaYszSCse34EHpPYAP14gVtlpMcukkTV3c6WMEVBGVgla7GU7i1L X-Received: by 2002:aa7:dacc:: with SMTP id x12mr4307982eds.98.1614357130318; Fri, 26 Feb 2021 08:32:10 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1614357130; cv=none; d=google.com; s=arc-20160816; b=WoSW3tZwoxgD3TDLVf/Rzqerl5wuSztenY1DU4i+BMKyu9ZN6TCfXBSjQRotyCG11E ZSynkW2D+haxPZGF4YzR0fwQ33sRs6B5gXmEE8aFvtFBtZP0l+lfFVFV60QbXc9FfpUx JLzg7n9E7KeYXNDY4fzqdDpiSl4OrmvEStOxaU6siebFUFByFsg1NBufPHa9rtR2ksh4 P1txXYiCvZCA/gcwWVAnYxex3alxh/e7cSxYfiHqF5xd1elTUKg3qRdaukGu83UG3Env ZgJ21L55zNamsLXHHgMs2e+XFyeW8jzHtFEewJ9G1ytXxFyjdN8lEdERakdkyB80q+tk 8i1w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:user-agent:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date; bh=8utl5QRrrwSk3WDQtOl/SkXVU3zELwDQjRmx5mz0Tgg=; b=zYcQ6UwP3P1bL4gpmop0ExXZ2mWRHHM3S4pg785MqsS0BhvhWSs5t7QRaJAitneyn0 HjQ6cCHfDUYoFHWBKs5XGsuhIJEOdmWZ1LQDDTkguJCJMbPYQft+t4rh86uyLm4AFgxl X8g4k7FH3VIjSR9LZBGnlWwF8p/rVLvmN7Kv0pOrvYHJzgoHSkG3vGaqa7wkFwWoA82t 82+1dSEqBvdgeFpcmNDZRR5GstEr2daj54XJQ4fcpbHAbTGBKt9uZuu/XjoentAiu0Kj /vdKr+uMetSs2AOdh+TJKg2WXhAVRl5vf/lHYdp047y+W9hWSW+00UHENnApwT5AzzDa eilg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id 8si6123985ejz.244.2021.02.26.08.31.45; Fri, 26 Feb 2021 08:32:10 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230041AbhBZQat (ORCPT + 99 others); Fri, 26 Feb 2021 11:30:49 -0500 Received: from netrider.rowland.org ([192.131.102.5]:36749 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S230063AbhBZQar (ORCPT ); Fri, 26 Feb 2021 11:30:47 -0500 Received: (qmail 1393779 invoked by uid 1000); 26 Feb 2021 11:30:04 -0500 Date: Fri, 26 Feb 2021 11:30:04 -0500 From: Alan Stern To: Longfang Liu Cc: gregkh@linuxfoundation.org, mathias.nyman@intel.com, linux-usb@vger.kernel.org, yisen.zhuang@huawei.com, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] USB:XHCI:Modify XHCI driver for USB2.0 controller Message-ID: <20210226163004.GB1392547@rowland.harvard.edu> References: <1614327697-1021-1-git-send-email-liulongfang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1614327697-1021-1-git-send-email-liulongfang@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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