Nouveau - Apr 2021 - How to use DIX with nouveau GUI driver, instead of DDX?

My illustrious Nouveau list leaders,

Namaste. Good morning.

Before posting I searched Google using your tool for the string ["set
up DIX" nouveau site:lists.freedesktop.org]

I don't have a programming background. But I chose 'Freedom' to be
with FSF movement and software for 12 years. I have been consistently
using mostly Knoppix and Debian, sometimes, Ubuntu, and rarely, Puppy,
for my regular work, that includes image and text editing.

I have an old but still very functional laptop with MCP79 [GeForce 8200M
G] (rev b1) (prog-if 00 [VGA controller] card with my laptop's
motherboard. The audio device : NVIDIA Corporation MCP79 High
Definition Audio (rev b1)

Since beginning, I have been using the proprietary nvidia 32 bit
drivers, as nouveau didn't work of my system. It froze the system
every time init 5 was booted into, with the first  GUI drawing.

I have't had any problems with nvidia so long as my system ran 32bit,
so I just carried on with my work. I am a regular Debian-user ML and
Debian forum user.

Then when 64bit packages became available I faced my first difficulty
with nvidia while installing a fresh Debian Distro with a new HDD.

Only recently, I have learnt and tested (temporarily with Knoppix
persistent non-iso install) how to have nouveau use DIX instead of DDX
 tech.

A kind gentleman helped by giving me this precious information in this
regard on the Debian-user ML.

It apparently irrationally involves letting nouveau driver set
up GUI on first init 5 boot. Which immediately freezes my system.

I then reboot into init 3, with "apt-get purge
xserver-xorg-video-nouveau"
the said package and again reboot.

When I boot again into init 5, the DIX instead of DDX is set up and the GUI
interface works very well, using the video card.

I am puzzled. Isn't there a saner way to have nouveau use DIX in the
first place, rather than freezing the system using DDX?

I shall proceed to install Debian latest
firmware-10.9.0-amd64-netinst.iso with the next 1-2 days but I am
really confused for the situation involved.

I am ready to run whatever tests you want me to run with whichever
codes, and shall upload those outputs to my Google Drive for your kind
perusal.

Since I am only a user and don't have a programming background, I
wouldn't like to join the mailing list, as I shall not be able to
help.

Best.

Rajib Bandopadhyay
A dedicated Debian and Knoppix user