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?
next prev parent 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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