Weston screen-share module with ivi-shell and ivi-controller.

[Maciej Pijanowski]

On 28.09.2020 16:15, Tomasz Zyjewski wrote:
> Hello,
>
> I am using Weston with screen-share module. When a desktop shell is 
> used the
> screen-share module works fine. In that scenario, the weston.ini file 
> looks like
> follow
>
> ```
> [core]
> shell=desktop-shell.so
> modules=screen-share.so
> backend=drm-backend.so
>
> [screen-share]
> command=/usr/bin/weston --backend=vnc-backend.so 
> --shell=fullscreen-shell.so
> output-id=0
> ```
>
> The problem occurs when I try to use screen-share module with 
> ivi-shell and
> ivi-controller module from wayland-ivi-extension [1]. In that case, the
> weston.ini file looks like that
>
> ```
> [core]
> shell=ivi-shell.so
> modules=ivi-controller.so,ivi-output-controller.so,screen-share.so
> require-input=false
>
> [ivi-shell]
> ivi-input-module=ivi-input-controller.so
> ivi-client-name=/usr/bin/simple-weston-client
> bkgnd-surface-id=1
> bkgnd-color=0xFF000000
>
> [screen-share]
> command=/usr/bin/weston --backend=vnc-backend.so 
> --shell=fullscreen-shell.so
> output-id=0
> ```
>
> and the screen share module loading fails with `No wl_shm found` error
>
> ```
> [13:51:38.094] Screen share failed: No wl_shm found
> ```
>
> In screen-share I use vnc-backend module [2] which is not merged yet, 
> but the
> same results can be obtained when rdp-backend is used.
>
> It looks like screen-share module cannot find globals like 
> `wl_compositor` and
> `wl_shm` when `wl_registry_add_listener` is called [3]. I can tell 
> that none of
> the conditional statements are checked inside `registry_handle_global` 
> function
> [4].
>
> What's more, if ivi-control module is not loaded and I just use 
> ivi-shell then
> screen-share module loads successfully and `registry_handle_global` 
> function is
> executed.
>
> Any suggestions on how to further debug why the globals are not 
> available from
> screen-share module in that scenario are highly appreciated.


It looks like the main issue is that the second weston instance is using 
the same config
and tries to load the ivi modules (especially the ivi-controller module) 
as well. The solution
would be to pass the --config switch in the command in the screen-share 
section, to
a different weston config (could likely be even an empty one).

>
> Thank you
>
> [1] 
> https://github.com/GENIVI/wayland-ivi-extension/tree/9acdaa1a9c79558691b1513cc4917f2ced91af8a
> [2] https://gitlab.freedesktop.org/wayland/weston/-/merge_requests/362
> [3] 
> https://github.com/3mdeb/weston/blob/use_GL_RGBA/compositor/screen-share.c#L955
> [4] 
> https://github.com/3mdeb/weston/blob/use_GL_RGBA/compositor/screen-share.c#L711
>
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> wayland-devel at lists.freedesktop.org
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-- 
Maciej Pijanowski
Embedded Systems Engineer
GPG: 9963C36AAC3B2B46
https://3mdeb.com | @3mdeb_com