Re: [Xen-devel] [PATCH V4 3/7] libxl: add pvusb API

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

George Dunlap writes ("Re: [Xen-devel] [PATCH V4 3/7] libxl: add pvusb API"):
> On Tue, Jun 16, 2015 at 12:19 PM, Juergen Gross <jgross@xxxxxxxx> wrote:
> > I'm pretty sure this is just a matter of timing during boot: the busses
> > are all (or at least some of them) queried at the same time and the
> > first answering gets number 1, the next 2, and so on. And timing seems
> > to be different enough to result in unstable bus numbers.
> 
> Right -- I meant "stable in topology within one boot", but at least
> two of you have now understood me to mean "across reboots" by default,
> so that's obviously a detail that needs to be specified. :-)

I think "stable in topology within one boot" is nearly vacuous (or are
we expecting buses or devices to spontaneously renumber themselves for
no reason) and also nearly useless.

We definitely need _some_ way for a user to identify a specific device
uniquely in a way that is reliable from one boot to the next.  vid:pid
is one way to do this, but not always sufficient.

Ian.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel