Xwayland on demand (Re: [PATCH xwayland 3/3] xwayland: Handle the case of windows being realized before redirection)

[Carlos Garnacho]

Hi Adam & Pekka,

On Thu, Jan 17, 2019 at 9:23 AM Pekka Paalanen <ppaalanen at gmail.com> wrote:
>
> On Wed, 16 Jan 2019 14:05:01 -0500
> Adam Jackson <ajax at nwnk.net> wrote:
>
> > On Wed, 2019-01-16 at 11:52 +0200, Pekka Paalanen wrote:
> >
> > > What I think we would need is a way to launch Xwayland, but ensure it
> > > does not process the real X11 apps until all the preparations (xrdb,
> > > XWM init, etc.) have finished. What the preparations are exactly, only
> > > the Wayland compositor (the desktop) will know.
> >
> > Who's launching this first X11 app, and why are they unable to defer
> > launching it until the Xwayland is prepared? There's quite a few ways
> > we could add this kind of interlock to setup, I just want to clarify
> > which problem we're solving first.
>
> Hi Adam,
>
> any user action could be starting the very first real X11 app:
> - user clicking a launcher icon on the desktop, e.g. for a game
> - user issuing a command in a shell in a terminal window
> - a Wayland app launching another app that just happens to be an X11 app
>
> In the current setup of on-demand Xwayland, the Wayland compositor will
> be listening on the X11 DISPLAY socket. When the Wayland compositor
> sees the first X11 client attempting to connect, it will launch
> Xwayland process and passes the listening socket to it.

That's exactly what I did too for mutter at
https://gitlab.gnome.org/GNOME/mutter/commits/wip/carlosg/xwayland-on-demand

Cheers,
  Carlos