nixos/nvidia: assert open option is manually set on drivers >= 560

[getchoo]

Description of changes

This requirement was introduced in #337289 as a way to make sure users "explicitly pick which version of the driver they want since nvidia recommends the open one, but that is incompatible with older drivers". This is reasonable, however the user isn't informed in any real way aside from the upcoming release notes

This has caused a good amount of confusion amongst users. By introducing this assertion and using a new useOpenModules local variable, we can have the same behavior but display a proper error message to hopefully clear things up until we can safely make this a default

#338362 was also mentioned as an alternative to this here, however given our special case of it only needing to be set sometimes, I believe giving this message explicitly is a lot more user friendly

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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Add a 👍 reaction to pull requests you find important.

[Kranzes]

I think there are some implications to this change that need to be considered. Nvidia does not recommend and does not support (?) GPUs prior to Turing with the open drivers. This change might cause the GPU to stop working for users with an older Nvidia GPU.

[getchoo]

This change might cause the GPU to stop working for users with an older Nvidia GPU.

What part of this change exactly? No defaults are being set here; it's only explicitly documenting the requirement of setting this option, as introduced in the above PR. The only change will be the error message when this option isn't set

[Kranzes]

I've not been following too closely the history of this module but it seems this change now sets a default value to the open option. I think previously you had to pick a version, but with this change it will just default to open which may break systems with older GPUs.

[kanashimia]

but with this change it will just default to open which may break systems with older GPUs.

No, there is an assertion that tests cfg.open != null

[kanashimia]

Why is it here and not where the other assertions are?

[getchoo]

I believe the open modules support the datacenter drivers as well, so putting this behind the nvidiaEnabled conditional (which only checks if services.xserver.videoDrivers includes "nvidia") with some of the other assertions could cause this to not work in the event of only hardware.nvidia.datacenter.enable being set

[kanashimia]

It could also fixed by allowing to define custom message for such options. #338362 improved message, but it is still bad because it isn't custom. @SuperSandro2000
Personally I think assertions are good enough.

[SuperSandro2000]

LGTM

[kanashimia]

Looks good