Re: wireless-regdb: Allow 6ghz in the US

Hi,

On Thu, Mar 6, 2025 at 4:02 PM Johannes Berg <[email protected]> wrote:
>
> Uh, this is a complex discussion. I do believe that we simply do not
> have a way to capture the complexity of the rules in the database today.
>
> Skimming the documentation, it seems that:
>
>  * Paragraph 56: For AP operation, it is allowed to operate an LPI AP
>    (indoors, obviously) - we could capture that with NO_OUTDOOR and
>    that's what the rule has now.
>  * Paragraph 122: For client operation, passive scanning is required,
>    presumably because clients are assumed to be mobile and thus also
>    present outdoors, where they will also scan.
>    This can only be captured with NO_IR today.
>  * There are additional spectral density power limits in paragraph 59,
>    which cannot be captured by the database today.
>
> However, the combination of these really cannot be captured - NO_IR will
> also prevent AP operation, which I think is the issue discussed in this
> thread, but removing NO_IR will make clients break Paragraph 122.
>
> I'll note that in general scanning on the 6/7 GHz band, by 802.11 spec,
> is only active on the few Preferred Scanning Channels (PSCs), however,
> that'd _still_ break Paragraph 122.
>
>
> Unfortunately, it's also hard to fix - we cannot remove NO_IR because
> that's used by older kernels, so I think the only way to fix it would be
> to add a flag a la NL80211_RRF_ALLOW_6GHZ_VLP_AP (which translates to
> IEEE80211_CHAN_ALLOW_6GHZ_VLP_AP) which overrides NO_IR for this
> specific case.
>
> We also have reg_rule->psd internally already, I guess we just never
> added a way to convey it from userspace? Not sure what it even does
> though.

I wonder if it is worth bringing up this topic in the networking track
at Plumbers this year? It would be about the various limitation of
wireless-regdb today, such as:
- lack of PSD
- only one rule per band, preventing things such as
  - AP on 6 GHz in the US, as this thread mentions
  - very low power outdoor usage vs higher power but indoor-only usage

That said, I'm not in a position to implement anything to improve the
status quo.


ChenYu