Re: [Qemu-devel] [PATCH 6/6] qdev: Generate IDs for anonymous devices

[Gleb Natapov <gleb@redhat.com>]

On Wed, Aug 31, 2011 at 08:31:26PM +0200, Jan Kiszka wrote:
> On 2011-08-29 23:19, Anthony Liguori wrote:
> > On 08/29/2011 03:56 PM, Jan Kiszka wrote:
> >> On 2011-08-29 21:23, Anthony Liguori wrote:
> >>> On 08/26/2011 09:48 AM, Jan Kiszka wrote:
> >>>> In order to address devices for that the user forgot or is even unable
> >>>> (no_user) to provide an ID, assign an automatically generated one. Such
> >>>> IDs have the format #<number>, thus are outside the name space availing
> >>>> to users. Don't use them for bus naming to avoid any other user-visible
> >>>> change.
> >>>
> >>> I don't think this is a very nice approach.  Why not eliminate anonymous
> >>> devices entirely and use a parent derived name for devices that are not
> >>> created by the user?
> >>
> >> This eliminates anonymous devices completely. So I guess you are asking
> >> for a different naming scheme, something like<parent-id>.child#<no>
> >> e.g.? Well, we would end up with fairly long names when a complete
> >> hierarchy is anonymous. What would be the benefit?
> > 
> > No, I'm saying that whenever a device is created, it should be given a
> > non-random name.  IOW, the names of these devices should be stable.
> > 
> >> I'm really just looking for some simple, temporary workaround without
> >> touching the existing fragile naming scheme. What we really need is full
> >> path addressing, but that without preserving all the legacy.
> > 
> > Yeah, I understand, and I hesitated making any grander suggestions here,
> > but I'm not sure how much work it would be to just remove any caller
> > that passes NULL for ID and replace it with something more meaningful. I
> > think that's a helpful clean up long term no matter what.
> 
> That won't solve the problem of finding a unique device name. If we want
> to derive it from stable device properties (bus addresses etc.), we
> first of all have to define them for all types of devices. And that's
> basically were the discussion exploded last year IIRC.
> 
Why not use the OpenFirmware naming that we already have for some
devices instead of inventing something new?

--
			Gleb.