[PATCH weston 1/3] window: use roundtrip instead of dispatch after get_registry

[Marek Chalupa]

On 12 December 2014 at 13:24, Pekka Paalanen <ppaalanen at gmail.com> wrote:
>
> On Fri,  5 Dec 2014 13:49:40 +0100
> Marek Chalupa <mchqwerty at gmail.com> wrote:
>
> > wl_display_dispatch() just dispatches events that are in
> > default and display queues and if there are no events,
> > then it will wait for them. But only dispatching
> > the events doesn't guarantee that we got all the global announcements,
> > we need to do sync too. Therefore use wl_display_roundtrip() instead
> > of wl_display_dispatch().
> >
> > Signed-off-by: Marek Chalupa <mchqwerty at gmail.com>
> > ---
> >  clients/window.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/clients/window.c b/clients/window.c
> > index cc1e272..c5082ba 100644
> > --- a/clients/window.c
> > +++ b/clients/window.c
> > @@ -5527,7 +5527,7 @@ display_create(int *argc, char *argv[])
> >       d->registry = wl_display_get_registry(d->display);
> >       wl_registry_add_listener(d->registry, &registry_listener, d);
> >
> > -     if (wl_display_dispatch(d->display) < 0) {
> > +     if (wl_display_roundtrip(d->display) < 0) {
> >               fprintf(stderr, "Failed to process Wayland connection:
> %m\n");
> >               return NULL;
> >       }
>
> Very true, pushed.
>
> I tried to look quickly, but I couldn't see it; the globals that send
> initial events on bind, like wl_shm.format - do we have the 2nd
> roundtrip for those somewhere?
>
>
Nope, not in display_create() (or functions called from it). However, in
the current code everything that depends
on the wl_shm.format (which is the only bind in global handler) is called
from some handler (if I haven't overlooked something),
so it works, because the handler is called after the wl_shm.format is
processed.

Nevertheless, In the future it could get broken, because some functions
that depend on wl_shm.format
are not static, so if programmer use them right after display_create(), the
wl_shm.format events do not need to be
dispatched by that time.

So maybe follow-up patch would be good.


>
> Thanks,
> pq
>

Regards,
Marek
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