Re: iw reg get since iw-4.x

[Johannes Berg <johannes@sipsolutions.net>]

On Fri, 2017-05-12 at 17:11 +0300, Sergey Naumov wrote:
> Hi All.
> 
> I see that since iw-4.x "iw reg get" reports multiple region
> information - per-phy and global. Moreover, per-phy information could
> be marked as "self-managed".

That's also dependent on the kernel.

> Could somebody clarify when a driver uses phy-specific region and
> when
> - the global one?

It's just a driver decision, and how the firmware works.

> Looking at a list of channels from "iw phy phyX info" I can conclude
> that if "self-managed" is true, then phy-specific region is used,
> otherwise - the global one. Is it a correct assumption? If yes, then
> why phy-specific regions are reported at all for non-self-managed
> devices, and why the global region is reported for self-managed ones?

Good question, I'm not sure right now. You probably need to look at the
kernel's code (net/wireless/reg.c) to figure out the answer.

> I think it would be natural to use new "iw phy phyX reg get" command
> to report region information that is actually used, but unfortunately
> this command returns exactly the same as "iw reg get":

It's a pure alias right now, but that could be fixed by filtering in iw
I guess.

johannes