Re: [PATCH V3 2/2] cfg80211: support ieee80211-freq-limit DT property

[Johannes Berg <johannes@sipsolutions.net>]

> When driver uses custom regulatory it registers initial channels at
> init but it can also react to regdom changes using reg_notifier. Is
> that correct?

We can treat regulatory and OF data as entirely independent, I think.
At least that's my suggestion:

 * use OF data to populate the original channel list, saying which
   channels are valid (or not)
 * use regulatory later to further restrict settings of the channels

> So I'm looking at brcmf_cfg80211_reg_notifier which calls
> brcmf_setup_wiphybands which calls brcmf_construct_chaninfo.
> That last one reworks all channels on every call. It first marks all
> existing channels as DISABLED then queries firmware for the list of
> supported channels and updates wiphy channels one by one.
> So if I understand this correctly, every regdom change can result in
> rebuilding channels pretty much from the scratch. That's why I
> believed I need to call wiphy_freq_limits_apply on runtime, not just
> during the init.
> 
> Is there some flow in my understanding?

I think maybe there's a problem in my understanding :)

All the regulatory code usually takes into account channel->orig_flags. 
If this code also did, then we could have the original DISABLED flag
taken from OF still be valid here.

johannes

johannes