From mboxrd@z Thu Jan  1 00:00:00 1970
From: Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH V4 3/7] libxl: add pvusb API
Date: Tue, 16 Jun 2015 13:25:17 +0200
Message-ID: <5580079D.6070007@suse.com>
References: <1433906441-3280-1-git-send-email-cyliu@suse.com>	<1433906441-3280-4-git-send-email-cyliu@suse.com>	<CAFLBxZbVXjj-VM4KLdhqBkpC0qSR_sy3mNnSZAJQJmHuo4ZC0Q@mail.gmail.com>	<21887.64856.265751.921367@mariner.uk.xensource.com>	<558000E5.9000803@suse.com>
	<21888.1058.681450.470806@mariner.uk.xensource.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="windows-1252"; Format="flowed"
Content-Transfer-Encoding: quoted-printable
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <21888.1058.681450.470806@mariner.uk.xensource.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>, Ian Campbell <ian.campbell@citrix.com>, George Dunlap <George.Dunlap@eu.citrix.com>, Chunyan Liu <cyliu@suse.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Jim Fehlig <jfehlig@suse.com>, Simon Cao <caobosimon@gmail.com>
List-Id: xen-devel@lists.xenproject.org

On 06/16/2015 01:10 PM, Ian Jackson wrote:
> J=FCrgen Gro=DF writes ("Re: [Xen-devel] [PATCH V4 3/7] libxl: add pvusb =
API"):
>> On 06/16/2015 12:41 PM, Ian Jackson wrote:
>>> Is the busid more stable in the face of plug/unplug ?  This is the
>>> normal reason for a more path-like device specification.
> ...
>> Unfortunately the busid isn't stable at least across reboots.
>
> I see.
>
> Presumably the busdev isn't either.  We need to be let users specify
> something that _is_ stable, obviously.
>
> On my netbook I have this kind of thing in /etc/fstab:
>
> /dev/disk/by-path/pci-0000:00:1d.7-usb-0:1:1.0-scsi-0:0:0:0-part1 /media/=
usb1 auto rw,user,noauto 0 0
>
> Is a similar specification possible ?
>
>> qemu does support specifying a USB device via <vendorId>:<productId>,
>> which is stable even across reboots, but unfortunately it isn't
>> guaranteed to be unique (you can have plugged in two devices of the
>> same type).
>
> Indeed.  That would also be a thing we should allow people to do.
>
> AIUI some devices have serial numbers, which means you can distinguish
> them ?

Yes, they have. The question is whether those are different on multiple
instances? With "lsusb" I've found a device with serial number
0123456789ABCD. Do you really believe I'm just lucky owning the one with
such a nice serial number? ;-)

Juergen