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

[Jan Kiszka]

On 2011-09-07 11:50, Gleb Natapov wrote:
> 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?

Because I do not want to establish any path names before QOM conversion
(including potential device reorganization) has been started.
Specifically as I do not need naming for "some" devices, but for all.

Jan

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