[question] can multiple compositor share surfaces

[Damian Ivanov]

Thank you for the info & link.

On Wed, May 22, 2019 at 9:11 AM Simon Ser <contact at emersion.fr> wrote:
>
> On Tuesday, May 21, 2019 6:56 PM, Damian Ivanov <damianatorrpm at gmail.com> wrote:
> > Hello Simon,
> >
> > I imagine many possible usecases for example:
> > Two compositors, one crashes the surfaces are not deleted and you are
> > logged out to your gdm/sddm login vt, but the other compositor takes
> > ownership of the surfaces and starts another 'backup compositor' or
> > another example would be an alternative approach for remote control.
> >
> > Is two compositors sharing surfaces currently technical possible with wayland?
>
> This is not possible with the Wayland core protocol.
>
> In the X11 model, the X11 server has ownership over the windows, but
> allows X11 clients to manage windows (WMs). In case the X11 server
> dies, the whole session gets lost (same as a Wayland compositor dying).
> Obviously this also has security implications.
>
> This is not "surface sharing" though. It's "one process owns the
> surfaces and another manages them".
>
> It would certainly be possible to design a protocol that would allow
> some Wayland clients to become "WMs". It's not obvious to me that it
> would work well (it would be easy to mess up the "each frame is
> perfect" design of Wayland, add complexity, add latency, etc). This is
> also not something that would work in all compositors.
>
> But if you're a compositor writer, this is technically possible.
>
> Side note, crash resistance is something that has been investigated by
> the Arcan project. I haven't looked at it in detail, but here's an
> article about it:
> https://arcan-fe.com/2017/12/24/crash-resilient-wayland-compositing/
>
> > On Tue, May 21, 2019 at 4:06 PM Simon Ser contact at emersion.fr wrote:
> >
> > > On Tuesday, May 21, 2019 2:44 PM, Damian Ivanov damianatorrpm at gmail.com wrote:
> > >
> > > > Hello,
> > > > Is it possible for two separate compositors to share the same list of
> > > > surfaces or connect to the other compositor and receive the surfaces
> > > > or connect to the wayland-0 file and receive new surfaces as well?
> > >
> > > Hi,
> > > Can you explain what you're trying to achieve? What is your end goal?
> > > Thanks,
> > > --
> > > Simon Ser
> > > https://emersion.fr
>
>