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

[Anthony Liguori]

On 02/23/2012 08:08 AM, Markus Armbruster wrote:
> Luiz Capitulino<address@hidden>  writes:
>
> > On Thu, 23 Feb 2012 08:50:08 +0100
> > Markus Armbruster<address@hidden>  wrote:
> >
> > > Kevin Wolf<address@hidden>  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<address@hidden>
> > > > > ---
> > > > >   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