[Interest] Running Qt application on Linux without screen

[Tomasz Olszak]

Update:

1. Weston has WIP patch to enable force-on option for output.
    This makes output always connected and Qt apps works with this option.
    However when I started weston without screen connected I encountered
    a crash from intel i915 driver with intel_dp_compute_config on top
of stacktrace
2. I found out that I can enable certain output from kernel by passing
e.g. video=HDMI-A-1:1024x768e.
    That fixed kernel bug and weston tweak was not necessary anymore.
I also am able to use eglfs plugin.
    Unfortunately it seems that eglfs plugin doesn't handle monitor
connection after application is started
    So there is no way to move my app to new screen once is is available.
3. I ended up with forcing from kernel the only used HDMI output.
    If device is booted without screen then eglfs window with 1024x720
resolution is created.
    Once screen is connected it gets such resolution.
    If device is booted with screen connected then it get the most
appropriate resolution.

Hopefully it is not so complex to fix it in eglfs,
If I find some time I will look at it. Weston definitely handles
monitors hotplug - unfortunagtely it is not possible to move window
from one display to another using wayland qpa.
Additionally if I understand correctly Qt wayland compositor is meant
to work with eglfs plugin so it needs to have monitor hotplug
handling.





2018-06-19 10:24 GMT+02:00 Christian Gagneraud <chgans at gmail.com>:
> On 19 June 2018 at 18:49, Tomasz Olszak <olszak.tomasz at gmail.com> wrote:
>> It needs OpenGL and 60fps from camera.
>>
>> Anyway I got some hints from QtWayland maintainer and hopefully small patch
>> will allow me to use wayland without screen and show application on real
>> screen once it is available.
>>
>> Will let you know once I finish and test it.
>
> Please do, that's an interesting setup.