So, before we're back to the (good ol') forum, i was asking about how can i set or test resolutions with xrandr, if...
...don't work on F3 tty. I was trying with this and all i can obtain was
No protocol specified
Can't open display :0.0
Reading, it was probably a user permission issue (but we're running root! WTF.), so after burning my brain up, i give up with a solution: Calling xterm from PCmanfm
After Batocera boots, press F1 for bring PCmanfm. On "Edit" menu, press "Preferences". Select "advanced" menu. There's a white line on "Programs" for "Terminal Emulator". Here, write "xterm" without the quotes. Press "close" button. Then, on "Tools" menu, select "Open Current Folder in Terminal". Et voila! A white screen with...
...will appear. Thats it. Since we're working on the graphical side of things, xrandr will work directly.
By the way, on my 2 laptops with 5.24, when manually select the Video Output from ES (with intel's HD 3000 and HD 4000 at least), after reboot, output doesn't change. Stays in LVDS1...so! On your new and shiny xterm window...
cp /etc/X11/xinit/xinitrc ~/.xinitrc
And on the xrandr lines you have to specify what output you want and the resolution (or set the modes supported)...an example:
xrandr --output XXX --mode AAAxBBB
Being XXX your output of choice and AAAxBBB the resolution available. And if you have any issues on laptop, better deactivate LVDS1. Put this line before the output assigned...
xrandr --output LVDS1 --off
This will switch off the laptop's internal display. If by any chance you have to makes changes (because you disconnect the output, for example...), call tty from F3 (Alt+Ctrl+F3) and make changes from there (editing .xinitrc with nano)
Cheers and happy holidays!