[Solved] How to set desktop resolution without monitor?

[foormanek]

Hello,
I connect to headless sparky box via x11vnc. X11vnc starts as my autologin user autorun command. After connecting I see my desktop and everything works, only the resolution is too small, some 1024x768 or so. I can not change resolution normally - there is no monitor to choose from and I have no resolutions to choose.  I can change resolution via "xrandr --fb 1920x1080" command, resolution changes, but with black bands right and down to old blue sparky wallpaper. I even could use that, but status panel remains in the middle of the screen and gets in the way.
How to change resolution and have desktop do resize itself to it? Or set a higher resolution upfront, when my desktop starts?

[jidan]

What's your desktop environment?

[foormanek]

What's your desktop environment?

LXQt, as recommended with sparky. Everything is on defaults.
In the meantime LXQt guy posted a solution how to resize desktop after resizing framebuffer
https://forum.lxqt.org/t/resize-desktop-after-resizing-framebuffer/1034
so this trick I know now, but I would like to do it better. Higher resolution from the start or a script to do it with one click or else...

[jidan]

You can use a dummy monitor. Install it with:

Code Select Expand

sudo apt-get install xserver-xorg-video-dummy
Then you can configure it using xorg.conf (driver "dummy") or using monitor configuration.

[foormanek]

You can use a dummy monitor.

I did what you wrote. I have put "dummy-1920x1080.conf" in /etc/X11/xorg.conf.d, config found here:
https://techoverflow.net/2019/02/23/how-to-run-x-server-using-xserver-xorg-video-dummy-driver-on-ubuntu/
Now my headless sparky starts with 1920x1080 desktop, just as I needed.
Thank you!

[jidan]

Welcome :)
Just remember to deactivate it when you decide to plug a real monitor.