seth wrote: Just having the files installed should not provide an nvidia-drm driver match…?

The problem is that the files matched on the intel driver and made them to use modesetting. So, just by having the nvidia package installed, would prevent one from using the intel DDX driver, even if you made a /etc/X11/xorg.conf.d snippet saying you wanted to use that.

seth wrote: Making the nvidia GPU primary will make it (drummroll) the primary GPU (unless it's deactivated and the kernel module not loaded through eg. bbswitch what, I assume, simply covered this usecase before)

Yes, it was ok for optimus setups to have that option, because: a) when using bumblebee it simply didn't matter b) using nvidia-xrun and optimus manager is the same as reverse prime, so it didn't matter either. With the new prime render offload method, it does matter, because it forces the nvidia card to the the primary effectively using reverse prime.

seth wrote: If you've a multi-GPU system, you'll have to tell the server which GPU to use. One way or another. It's just that different groups of users will tend to have different preferences.

(Which is why I'd tend to agree that no package should implicitly select the primary GPU for the user)

You'll also have to define a sink for the output provider if you want to use an output that's not wired to the used GPU.

You don't need to have a PrimaryGPU setting though. You use reverse prime to make outputs not available to the card doing the actual display, and xrandr can use all of them in one single Screen, so all is good. It's the same case when you have a MXM optimus setup, where one of the outputs is wired to the nvidia card.

seth wrote: Just *having* an (empty) /etc/xorg.conf won't do anything and while you will have to write any configuration that is not covered by an installed package, PLEASE DON'T WRITE A STATIC XORG.CONF! Ever.

I used to think like that, but give how X configuration works, it doesn't matter if you use snippets or a xorg.conf. It's all merged into one single, let's say, meta conf and used. So, avoid all caps and it's perfectly fine to have a xorg.conf file.

seth wrote: And VERY MOST ESPECIALLY not using "X -configure" or "nvidia-xconfig" (no, also not through nvidia-settings)

I'd say that X -configure or nvidia-settings can give you a foundation file for you to work on. Don't blindly use them, but you can however get a basis to work on.

seth wrote: Instead add the preferred alterations into /etc/X11/xorg.conf.d

Doesn't matter these days (or did it ever?)

seth wrote: Maybe it'd be feasible to have mutually exclusive multi-GPU/optimus packages that provide the different configs, but otoh this is archlinux, so just "rtfw" ;-)

Not sure how that would work. Also, I think nvidia is going to make the AllowNVIDIAGPUScreens option the default in the driver in the future, so I don't even think the nvidia-prime package will have utility. You're perfectly right that users should RTFM.