I found this "driver" on the net I don't remember the exact link
here the link for the file I am using right now and it works:
https://tinyurl.com/e6cnryya

probably it has been modified or is it a beta I have no idea.
But the important thing is that it works well.
The file is dated 2018 and is about 136kb the one included in morphos 3.15 and about 146kb.
I am writing because only you can answer this and maybe I get more information and it is probably one of your files and maybe it can be developed further.

Installation is very simple after installing morphos 3.15
before rebooting just copy the "Radeon" file to sys: morphos / devs / monitor /
and replace the original one and then reboot.
At that point the cable I have DVI-HDMI works perfectly while with the original Radeon file included with morphos 3.15 it does not work in any way.
here two screenshots of the resolutions that are created automatically after reboot and use a monitor named "27G2G4"
https://imgur.com/dll1bd2
https://imgur.com/HQhXxIu

You have to close the lid of the PowerBook and after booting you can reopen it and use the keyboard without any problems the PowerBook screen will remain black.
While the external monitor will work smoothly with all applications including all mos-68k demo-scenes etc. video player games OWB WayFarer etc.

While with the original driver the demo-scenes open only on the powerbook monitor.

I tried with the tv and it always works perfectly with the hdmi

I hope the driver can be useful in some way and surely and the result of your work maybe it can be useful for future updates.

Now my question is this I tried to use it with the card that captures videos with hdmi socket I can record videos without problems with OBS but when I use the demo-scenes for example the screen is captured in this way here the video:
https://www.youtube.com/watch?v=fONVqzjZyVQ

in practice the screen is divided into small parts I think it is not a problem of OSB but of the "modified Radeon" driver that somehow sends the "output" out in this way.
I was wondering if it could be corrected somehow.
Strangely then the name of the monitor in use of morphos changes its name from "27G2G4" to "CaptureMode" when I use the capture card.
Thanks for any reply and sorry for the length of the text I tried to explain myself as best I could.
Thanks again.

[ Edited by white 23.08.2021 - 18:15 ]