Effort for upgrading from 1.3 to 1.5

[Pekka Paalanen]

On Thu, 20 Mar 2014 13:31:31 +0000
"Konopelko, Pavel (P.)" <pkonopel at visteon.com> wrote:

> Hello everybody,
> 
> Question:
> Given that somebody has Wayland/Weston 1.3 already integrated in
> their system, what would it take to upgrade to the upcoming
> Wayland/Weston 1.5?  Is this just a matter of re-building it and
> everything will continue working out of the box?  Are there any
> adjustments in the graphics stack (drivers, EGL support, etc.) needed
> to support 1.5?  Are there any adjustments on the application side
> needed to work with 1.5?

Hi,

oh, 1.3 seems like ages ago, I can't remember. But, looking at the git
history of few selected files should be enlightening, for instance in
Wayland src/wayland-client.h and src/wayland-server.h, and also the
protocol specification in protocol/wayland.xml. In Weston
src/compositor.h.

For clients, things are kept backward-compatible. For Weston plugins,
change from 1.n to 1.n+1 is not guaranteed to be compatible.

Libwayland API is stable and backward-compatible. The Wayland protocol
is also kept stable, but we are moving from wl_shell to xdg_shell,
though that probably does not concern you.

On EGL front, you probably should be looking at the history of the
specification files in Mesa, e.g.:
http://cgit.freedesktop.org/mesa/mesa/log/docs/specs/WL_bind_wayland_display.spec
to get an overview.

I think application side should just work, all in all.

> Background:
> The question is related to the weston-ivi-shell patch series
> submitted by Nobuhiko Tanibata.  This work is connected to the work
> that GENIVI [1] previously did in the area of IVI Layer Management.
> On the GENIVI side, the original plan was to propose the ivi-shell
> and the corresponding protocol to the Wayland project.  However, it
> was expected that it will take time to review and agree the
> protocols.  Until then the plan provided for adopting an out-of-tree
> patch based on Wayland/Weston 1.3 for GENIVI purposes.  Once the
> ivi-shell would be integrated in Wayland/Weston, GENIVI would switch
> to the upstream version.
> 
> Now that the patch series was well accepted and that only a few
> changes were suggested to the original protocol, it would make more
> sense for GENIVI to align with the upstream right away.  The only
> catch is that the content of the next GENIVI release is being
> finalized right now and the decision must be done quickly.  During
> the original reviews in GENIVI, using Wayland/Weston 1.3 as the basis
> was already approved.  The above question is an attempt to estimate
> the impact of adopting 1.5 instead.  Any hints and information on
> possible upgrade problems would be therefore greatly appreciated.

Sorry, I think "well accepted" may still be a slight overstatement at
the moment. It's just so hard to find time to review anything. When you
get a "looks good to me" then that's accepted by that particular
person, but even that is not enough to get into Wayland/Weston
upstream. For that you need to convince Kristian, who seems to be
extremely busy nowadays.


Thanks,
pq