Up to four (maybe more? if your card/s have the outputs/memory.

I use three 19" monitors @1280*1024 (3840*1024 desktop) fed from a pair of Nvidia Quadro FX 580 cards.

$ xrandr
Screen 0: minimum 320 x 200, current 3840 x 1024, maximum 8192 x 8192
--- snip ---
$

For a short time installed a fourth 15" monitor just to see if/how it worked, took it down for lack of space.
No serious problems save some artifacts in the centre monitor which the Nvidia driver did not have.

@greenjeans

Yes, it was a hassle.
But once you got it down pat, it worked perfectly well.

To wit:
Once I managed to write up a properly working xorg.conf for the first Linux distribution I tried, first with two and then with three monitors (cannot recall which) it was just a question of transplanting it to all the other distributions I tried out without having to touch it: it just worked® in all of them, including my first Devuan (Jesse) and so on with Devuan till the demise of the 340XX driver in Chimaera.

The only problem I see with nouveau is that it seems impossible to see under the hood, so to speak.
ie: just what is the layout of the xorg.conf file I am using now?

That should not be so as the configuration file, if it exists, gets priority.

Best,

A.

Note: you can have two monitors with nouveau.

Cool beans, back in the day it didn't so I had to use proprietary stuff, I really don't miss flailing about in xorg.conf one bit.

My old GT218 works without the firmware, but as Altoid mentioned, there are a lot of complaints about missing firmware. I don't recall if I could see any difference when I finally installed the firmware.

Note: you can have two monitors with nouveau. The monitor settings in xfce, lxde and lxqt will let you configure two monitors. (maybe more - I never tried three).

And the solution was?

Sorry, I was rushing yesterday trying to get some stuff done before the windstorm hit. (I did not succeed).

The firmware package is not in Daedalus proper, it's in backports, which I forgot I had enabled. So technically nouveau should have some functionality without it. You may or may not get more by adding the firmware package.

I once had a question about this.

TL;DR
It seems that, using nouveau, you do have to have firmware-nvidia-graphics installed, whether you need it or not.
Otherwise you get some bitching in dmesg.
ie: if you use nouveau but your specific Nvidia hardware is not on that list (~4.5mmb on disk), you obviously do not need those firmware files in your system.

See here: https://dev1galaxy.org/viewtopic.php?pid=51169#p51169

Best,

A.

Solved on IRC.

And the solution was?

A standard Devuan install (daedalus) already comes with libdrm-nouveau2 and xserver-xorg-video-nouveau, but do you also need the package firmware-nvidia-graphics to use nouveau?

Working on some Vuu-do updates, and just realized I hadn't included that firmware package. I stay away from the proprietary stuff as some of it conflicts with each other and I don't have a machine to test what works. But I want to be sure a user has at least nouveau to use if they have an nvidia machine.

Thanks!