[RFC][PATCH] dix: Skip PropertyNotify events if the property value didn't change

[Ville Syrjälä]

On Mon, Sep 20, 2010 at 05:47:59PM +0200, ext Keith Packard wrote:
> On Mon, 20 Sep 2010 08:35:11 -0700, "ville.syrjala at nokia.com" <ville.syrjala at nokia.com> wrote:
> > From: Ville Syrjälä <ville.syrjala at nokia.com>
> > 
> > Avoid sending PropertyNotify events with the same value in case the
> > value didn't actually change. Avoids waking up the clients needlessly.
> 
> getting timestamps fr
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala at nokia.com>
> > ---
> > I'm not sure if this kind of optimization is always legal or if some
> > specification says that the event must be sent even if the value doesn't
> > change. Hence the RFC.
> 
> Nope, any ChangeProperty request is required to generate a PropetyNotify
> event.

OK I was afraid of that.

How about when calling ChangeWindowProperty() internally in response to
some other stimuli? That was actually the case I was looking at when
this idea originally occured to me. Then again, that kind of thing may
be rare enough that making dix more complicated is not worth it. It's
always possible to fix the issue on the caller's side anyways.

-- 
Ville Syrjälä