Raspberry Pi 4 two monitors with extended screen

[Walter-X]

I've two monitors installed at the 2 hdmi ports of the raspberry pi 4.

I'm using raspbian buster lite without graphical gui.

Is it possible to configure the monitor settings not to be mirrored and set as one extended screen over the two monitors?

[rpdom]

Under the Preferences menu you should have something about screen settings or ArandR. That will show you the current setup for your screens.

You can drag the two screen boxes around to the configuration you prefer.
[edit] I should have read the original post more carefully. I did a Dougie and missed the "without GUI" bit

[wildfire]

I'm using raspbian buster lite without graphical gui.

Under the Preferences menu you should have something about screen settings or ArandR. That will show you the current setup for your screens.

You can drag the two screen boxes around to the configuration you prefer.

@OP I don't believe what you want is possible but I could be wrong.

[aBUGSworstnightmare]

Should be possible with legacy driver as it creates two framebuffer devices
Search the forum for a how-to

[HermannSW]

Should be possible with legacy driver as it creates two framebuffer devices

Wrong, the Pi4B does create only one framebuffer device, even if two HDMI monitors are connected.
So mirroring is all that is possible without X11.

[jamesh]

Should be possible with legacy driver as it creates two framebuffer devices

Wrong, the Pi4B does create only one framebuffer device, even if two HDMI monitors are connected.
So mirroring is all that is possible without X11.

Wrong Wrong. Using the legacy drivers (Disable FKMS) on Pi4 you will get two framebuffers, but you won't get 3D acceleration.

[6by9]

And using the DRM API you can attach whatever image planes you fancy to each of the screens, replacing the default mirrored frame buffer.
It all depends what you actually want to do on those two screens. Extending the console over two screens would be a very odd use case.

[wildfire]

Extending the console over two screens would be a very odd use case.

That's how I read it 6by9, it appears from the OP that that is what he wants to do though why? Clarification required I think.

Extend by width (why?) or extend by height (more feasible but again why?).

[HermannSW]

Thanks for correcting me, after disabling FKMS as jamesh proposed, really two framebuffers are there.

I just made my con_show tool display image on /dev/fb1 (1024x768, right), and raspivid preview show on 1360x768 /dev/fb0 left.
I did fill top 10 rows of both framebuffers with red/blue:

[Nightwing2012]

Thank you jamesh and 6by9 for that very informative item of comment out and use the old drivers. Doing a 4th gen con box myself.

Need to dig into how to do the DRM API image plane said in one post.