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From: Wang YanQing <udknight@gmail.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg KH <greg@kroah.com>, lkml <linux-kernel@vger.kernel.org>,
	linux-usb@vger.kernel.org
Subject: Re: [RFC]Is usb port number fixed?
Date: Sat, 21 Apr 2012 13:56:59 +0800	[thread overview]
Message-ID: <20120421055658.GA5277@udknight> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1204202028250.19313-100000@netrider.rowland.org>

On Fri, Apr 20, 2012 at 08:32:37PM -0400, Alan Stern wrote:
> In this particular case, it is guaranteed that the left USB port will 
> always be numbered as X-1.1:1.0 and the right port as X-1.2:1.0, where 
> the number X may change from one boot to another.  But the -1.1:1.0 and 
> -1.2:1.0 parts will always be the same.
> 
> This is because X is the bus number, which is allowed to change.  The 
> -1.1:1.0 and -1.2:1.0 values are port, configuration, and interface 
> numbers.  They will never change, because they come from the hardware.
Yes, configuration and interface come from the hardware,
but I don't know where the port come from, at least I don't think the port
comes from the same hardware with the configuration and interface, do you 
mean port come from the hub?

  reply	other threads:[~2012-04-21  5:57 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-20  9:25 [RFC]Is usb port number fixed? Wang YanQing
2012-04-20  9:37 ` Wang YanQing
2012-04-20 15:37   ` Greg KH
     [not found]     ` <CAHkwNT=VW8qF-7QRxpiaWkmQm0UFdsbahFLhT-PCc4OMnVs1Gg@mail.gmail.com>
2012-04-20 16:19       ` Greg KH
2012-04-21  0:32     ` Alan Stern
2012-04-21  5:56       ` Wang YanQing [this message]
2012-04-21 17:23         ` Alan Stern
     [not found] <CAHkwNT=DTjdhZmEg+SFGOVi+ZcS-NpHWH8Hh3XV+-BPzHRC7NA@mail.gmail.com>
2012-04-22 12:47 ` Alan Stern
2012-04-23  1:52   ` Wang YanQing
2012-04-23 15:13     ` Alan Stern
2012-04-24  2:16       ` Wang YanQing
2012-04-24 14:14         ` Alan Stern
2012-04-24 15:58           ` Wang YanQing
2012-04-24 14:22         ` anil
2012-04-24  2:24       ` Wang YanQing

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