Re: [Qemu-devel] [PATCH 5/5] qmp: add DEVICE_TRAY_MOVED event

[Anthony Liguori <anthony@codemonkey.ws>]

On 02/23/2012 08:08 AM, Markus Armbruster wrote:
> Luiz Capitulino<lcapitulino@redhat.com>  writes:
>
>> On Thu, 23 Feb 2012 08:50:08 +0100
>> Markus Armbruster<armbru@redhat.com>  wrote:
>>
>>> Kevin Wolf<kwolf@redhat.com>  writes:
>>>
>>>> Am 17.02.2012 20:21, schrieb Luiz Capitulino:
>>>>> It's emitted whenever the tray is moved by the guest or by HMP/QMP
>>>>> commands.
>>>>>
>>>>> Signed-off-by: Luiz Capitulino<lcapitulino@redhat.com>
>>>>> ---
>>>>>   QMP/qmp-events.txt |   18 ++++++++++++++++++
>>>>>   block.c            |   24 ++++++++++++++++++++++++
>>>>>   monitor.c          |    3 +++
>>>>>   monitor.h          |    1 +
>>>>>   4 files changed, 46 insertions(+), 0 deletions(-)
>>>>>
>>>>> diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
>>>>> index 06cb404..9286af5 100644
>>>>> --- a/QMP/qmp-events.txt
>>>>> +++ b/QMP/qmp-events.txt
>>>>> @@ -26,6 +26,24 @@ Example:
>>>>>   Note: If action is "stop", a STOP event will eventually follow the
>>>>>   BLOCK_IO_ERROR event.
>>>>>
>>>>> +DEVICE_TRAY_MOVED
>>>>> +-----------------
>>>>> +
>>>>> +It's emitted whenever the tray of a removable device is moved by the guest
>>>>> +or by HMP/QMP commands.
>>>>> +
>>>>> +Data:
>>>>> +
>>>>> +- "device": device name (json-string)
>>>>
>>>> For me, a device name is something related to qdev. 'device' is a
>>>> misnomer consistently used in all QMP commands so far and we can't fix
>>>> it any more, but at least the documentation should clarify what is meant
>>>> (that's for a follow-up patch).
>>>
>>> We can fix it if we really want to: rename, then add the old name as
>>> alias for backward compatibility.  Pick your favourite flavor of cruft.
>>
>> I like it, new events won't have the cruft.
>
> If we reserve "device" for device models, we need sensible names for
> device backends.  One each for block, net and char.  There's some
> precedence for "blockdev", "netdev", "chardev", but they contain "dev",
> so there's still some overloading of the name "device".  Better ideas?

For 1.2 (when QOM is considered stable), this should become pathname.  Given a 
path, a client can determine what the type of the object is (by reading the type 
property).

In fact, I'd like to see all events have a pathname of origin.  This would 
probably become part of the QMP protocol itself.

This gives us a mechanism to subscribe to events from specific objects.

Regards,

Anthony Liguori