Why does Java (XWayland / Weston) resize a Window to 1x1 pixel when HDMI is unplugged (and does not resize back when HDMI is plugged)

[Martin Petzold]

Hi Pekka,

Am 08.06.23 um 14:37 schrieb Pekka Paalanen:
> On Thu, 8 Jun 2023 14:21:31 +0200
> Martin Petzold <martin.petzold at tavla.de> wrote:
>
>> I am fixed to this Kernel, will be hard to get Weston 12 running.
> Hi,
>
> why would you say that? Did you try? Or do you mean that building
> Weston and a few dependencies (not kernel, not Mesa) from source is too
> much?

We are compiling our own kernel version for embedded i.MX8. Also the 
Debian is our custom build and we are able to adjust to other packages 
or compile parts. We know how to do that. However, we are fixed to 
5.10.52 for several reasons. And I need to cross-compile Weston then, 
which is maybe challenging?

I can try to compile on device and test. But which dependencies also 
need to be compiled then? XWayland? Wayland? Libraries?

>
> FWIW, when you unplug the last display, leaving none, then there is no
> display area. Weston does not pretend a fake display, there just is
> none. I don't know how Xwayland reacts to that, and how that Java suite
> reacts to what Xwayland does. Those would be something to look into, if
> Weston upgrade does not help.
Yes, it must be XWayland. Maybe there is any configuration to fix it?
>
> Xwayland might have a fake something when all real displays are gone,
> and maybe nothing then re-associates your app window from the fake
> monitor to a real monitor once a real monitor appears again? No idea.
>
> Maybe check what xrandr says while you have no displays connected? That
> might give a clue, assuming the Java stack listens to RandR.
>
Does xrandr really work with XWayland? I didn't install it with our 
change to Weston.

Thanks,

Martin