Pi4 HDMI setting incorrect on getting to desktop..script to fix?

[sparkypuzzler]

Hi all,

The issue:  I have a 4 way splitter on HDMI0 that is connecting to 4 identical monitors running 1920 1080.  Good quality vga cables are already in place to run the 4 remote monitors, and the HDMI to vga converter is obviously before the splitter.  It all works fine..but.....

On boot, despite me specifying in raspi-config and /boot/config.txt to specifically use group 2 and mode 16, the desktop ends up running at 1280 1024.  Somewhere along the way, I am guessing that the splitter or converter says back to the Pi that the resolution is 1280 and an auto-config running after the boot process adjusts output to that.  If I then manually go into Monitor Settings I can set the resolution to full HD and all the monitors display correctly!  But I can't get that setting to stick after reboot..something interferes with it.

I'm hoping that someone may know the easy solution.  But if not...... I think a little script to set the monitors to the full HD a few seconds after reaching the desktop is a definite solution.   I'm no expert and don't know where to put the command to make this happen, and also the structure of such a script.  I think it would be referenced/initiated from/in /home/pi/.config/openbox/autostart.sh  and have a delay of perhaps 10 seconds before working.

I tried for hours last night to get somewhere on this issue by changing settings without luck, so unless someone knows the reason, and easy method to change the setting on reaching desktop, I would really appreciate guidance on the script structure, activation and location.

cheers,