Provide regulatory.db info via /lib/firmware when supported

[dtzWill]

Issue description

Newer kernels (4.15+) can look for wireless regulatory info from /lib/firmware (for us this is /run/current-system/firmware I think?),
replacing the need for user-space helper like crda.
(at least in the common case, I believe)

Links to resources/related info

• https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/crda.git/commit/ <-- latest CRDA git adds note about this
• Not the same as the internal regdb, although I'm not sure the difference is as important for NiXOS'ers compared to other distributions. Info on internal: https://wireless.wiki.kernel.org/en/developers/regulatory/crda#config_cfg80211_internal_regdb
• https://bugs.archlinux.org/task/57563

[teto]

I don't want to hijack the thread but my problem may be related.
Recently, not sure why, I can't connect to an AP I previously could connect to so I suspect it's my machne (my phone can still access it), thus I've been looking at wifi information.
I used to have a plain error then I added udev.packages = [ pkgs.crda ]; while now it at least attempt to connect:

[    5.428896] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[    5.428898] cfg80211: failed to load regulatory.db

so I wonder if it's expected on nixos ?

NB: it's annoying all these errors when building kernels. do others have it too (I should probably look at hydras rather...

modinfo: ERROR: Module alias enable_fbc=1 not found.
modinfo: ERROR: Module alias enable_psr=2 not found.
depmod: WARNING: could not open modules.order at /nix/store/2bavdfzx904lyxzyj79avw111sgd1k78-linux-4.19.40-modules-shrunk/lib/modules/4.19.40: No such file or directory
depmod: WARNING: could not open modules.builtin at /nix/store/2bavdfzx904lyxzyj79avw111sgd1k78-linux-4.19.40-modules-shrunk/lib/modules/4.19.40: No such file or directory
building '/nix/store/hrqmhqypk383229adsv79h07g3cv4gdh-stage-1-init.sh.drv'...

[samdoshi]

To get the regulatory.db file loaded, you need to add wireless-regdb to hardware.firmware.

hardware.firmware = with pkgs; [ wireless-regdb ];

ls -l $(nix path-info nixpkgs.wireless-regdb)/lib/firmware to see the files.

Then you should see the following in dmesg:

[    2.532137] cfg80211: Loading compiled-in X.509 certificates for regulatory database

I haven't quite figured out what the best way to set the correct regulatory domain is however... short of just using iw.

[teto]

oh great thanks ! that was not obvious. I was looking for a setting to set on boot as a kernel parameter but haven't found it yet. Some interesting read https://wireless.wiki.kernel.org/en/developers/regulatory#kernel_integration suggests one can embed the kernel in the db as well ?!

https://wiki.archlinux.org/index.php/Wireless_network_configuration

[edolstra]

@samdoshi Something like this should work:

  boot.extraModprobeConfig = ''
    options cfg80211 ieee80211_regdom="NL"
  '';

Admittedly not ideal since it only works at module load time though.

[samdoshi]

Thanks @edolstra

Setting the following gives me the correct wifi config (check with iw reg get):

hardware.firmware = with pkgs; [ wireless-regdb ];
boot.extraModprobeConfig = ''
  options cfg80211 ieee80211_regdom="GB"
'';

Looking through the documents on:

https://wireless.wiki.kernel.org/en/developers/regulatory
https://wireless.wiki.kernel.org/en/developers/regulatory/crda

It seems to be a bit of a mess.... ieee80211_regdom is an 'old' option, but NetworkManager has no support for setting the reg domain.

I think having a module (hardware.wirelessRegulatoryDomain?) might be a very good idea, and such an option should be added tonixos-generate-config.

ArchLinux deals with it by using a custom udev rule to run iw when cfg80211 is loaded (source).

Another idea would be to added a networking.wireless.networks.<name>.country option, though that doesn't fix NetworkManager.

[stale]

Thank you for your contributions.

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[kloenk]

This should not be stale I think.

Should NixOS just add wireless-regdb to hardware.firmware as default?

[symphorien]

cc #121530

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/direct-firmware-load-for-regulatory-db-failed/16317/1