Re: [Qemu-devel] [PATCH] input: improve docs for input-send-event qmp command

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

> >> >  # @console: #optional console to send event(s) to.
> >> > +#           This parameter can be used to send the input event to
> >> > +#           specific input devices in case (a) multiple input devices
> >> > +#           of the same kind are added to the virtual machine and (b)
> >> > +#           you have configured input routing (see docs/multiseat.txt)
> >> > +#           for those input devices.  If input routing is not
> >> > +#           configured this parameter has no effect.
> >> > +#           If @console is missing, only devices that aren't associated
> >> > +#           with a console are admissible.
> >> > +#           If @console is specified, it must exist, and both devices
> >> > +#           associated with that console and devices not associated with a
> >> > +#           console are admissible, but the former take precedence.
> >> > +
> >> >  #
> >> >  # @events: List of InputEvent union.
> >> >  #
> >> 
> >> What is a "console", and how get input devices assoated with one?  I
> >> checked docs/multiseat.txt for clues, but found none.
> >
> > Oh, right, in the command line the video device names are used.  video
> > device emulation actually creates the consoles, typically console 0 is
> > your vga.  They are numbered in creation order.  You can inspect them in
> > the qom tree (/backend/console[$nr]).  There is a device link pointing
> > to the device which created it.
> 
> Begs the question why we're using console numbers in one place (QMP) and
> qdev IDs in another (command line).  Why can't we use one of them
> everywhere?  Or maybe support both everywhere?

Console numbers don't appear anywhere on the command line.  User doesn't
create consoles directly, only indirectly (via display device).

Supporting device (additionally to or instead of console) on qmp
certainly is an option.  IIRC that was briefly discussed, then we've
figured console number is simpler and in most cases not relevant anyway
(typical config doesn't has multiple input devices), and if you really
need it there are the qom properties to go figure.

> As long as we have both, documentation needs to stitch them together.
> Your explanation is a start, but it needs to be in a patch, not just in
> a mailing list archive :)

Sure.  Question is where to stick it best.

cheers,
  Gerd