Overriding a kernel module derivation that is getting including through NixOS configuration

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1

Hi,

I’m trying to override a kernel module facetimehd of the kernel I’m using in my flakes based nixos configuration:

{
  config,
  lib,
  pkgs,
  modulesPath,
  ...
}: let
  kernel =
    pkgs.linuxPackages_zen
    // { facetimehd = null; };
in {
  boot.kernelPackages = kernel;
};

Yet when I run the nixos-rebuild repl on my configuration, I see:

nix-repl> config.boot.kernelPackages.facetimehd
«derivation /nix/store/58hyyj7ccx3hv6hxyacagh2bll5j11xp-facetimehd-0.5.18-6.7.5.drv»

Whereas I do see that it gets overridden, if I try to manually override at REPL:

nix-repl> (pkgs.linuxPackages_zen // { facetimehd = null; }).facetimehd 
null

Any hints/ideas ?

Thanks!

2

Hi, @abbe.

I would explore adding the offending module to boot.blacklistedKernelModules.
This will create a /etc/modprobe.d/nixos.conf with a line blacklist facetimehd, which will effectively prevent it from being loaded.

See here for details.

Hope that it helps!

3

@pancho I’m not trying to blacklist it. I’m trying to update that module by overridding it with an update (which in this case, I just set it to null to save space while clarifying the intent, instead of providing an actual overrideAttrs invocation).

4

Oh, I see. Have you tried the patch route?

5

Patch to nixpkgs ? Nope. Because I think overrideAttrs way should work, and it’s not. So, I’m trying to understand why.

6

I meant this.

7

Maybe using linuxPackagesFor with the overriden derivation?
See the Linux Kernel entry on the Wiki for details, because the function does not appear if searched on search.nixos.org.

8

Thank you @pacho for the pointer to the needed documentation. linuxPackages_zen.extends was what I needed to override facetimehd module.

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