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Subject: Re: [RFC PATCH] USB:XHCI:Modify XHCI driver for USB2.0 controller
To:     Alan Stern <stern@rowland.harvard.edu>
CC:     <gregkh@linuxfoundation.org>, <mathias.nyman@intel.com>,
        <linux-usb@vger.kernel.org>, <yisen.zhuang@huawei.com>,
        <linux-kernel@vger.kernel.org>
References: <1614327697-1021-1-git-send-email-liulongfang@huawei.com>
 <20210226163004.GB1392547@rowland.harvard.edu>
From:   liulongfang <liulongfang@huawei.com>
Message-ID: <acfdf816-e295-df1d-4039-784fb0d417c4@huawei.com>
Date:   Sat, 27 Feb 2021 11:38:08 +0800
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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