Can't seem to use 5GHz APs with Intel wireless

[Cy Schubert]

In message <20180603174401.rbxa3fcnuoprogow at squirrel.exwg.net>, 
Christoph Moenc
h-Tegeder writes:
> ## Adam (amvandemore at gmail.com):
>
> > > 3. ifconfing wlan0 scan still doesn't show my 5Ghz only APs (at least som
> e
> > > I tested)
> > 
> > I don't believe the iwn driver is capable of 5gz.  At least mine doesn't
> > work on CURRENT.
>
> The iwn driver has code for 5GHz (I've no idea if that's complete).
> But looking at that reminded me: there are many "iwn" devices, including
> some having "BGN" appended to their names - I'd guess those devices
> don't support 5GHz aka 11a mode.

My iwn device (iwn0: <Intel Centrino Advanced-N 6205>) supports 5 GHz. 
I just disabled my 2.4 GHz APs and reassociated:

wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 
1500
	ether <MY_ETHER>
	nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
	media: IEEE 802.11 Wireless Ethernet MCS mode 11na
	status: associated
	ssid XXXXXXXX-5G channel 153 (5765 MHz 11a ht/40-) bssid <MY_BSSID>
	regdomain FCC country US authmode WPA2/802.11i privacy ON
	deftxkey UNDEF AES-CCM 2:128-bit txpower 23 bmiss 120 mcastrate 6
	mgmtrate 6 scanvalid 16959 ampdulimit 64k ampdudensity 8
	-amsdutx amsdurx shortgi -stbc -ldpc wme roaming MANUAL
	groups: wlan 

Some devices do and others don't. For example, I have an ath card for 
this same laptop (I swapped out my iwn card for an ath card for a short 
while) that supports station mode (BTW iwn firmware doesn't), 
discovering my ath device firmware does not support 5 GHz. I suspect 
that some iwn devices may be similarly "crippled", though the driver 
supports 5 GHz the firmware does not. My point is it's not a binary 
issue. You may need to Google your particular card to determine if the 
manufacturer has implemented the feature or not. I did for my ath card 
discovering not all implementations are equal. I wouldn't be surprised 
this might be true of iwn as well.



-- 
Cheers,
Cy Schubert <Cy.Schubert at cschubert.com>
FreeBSD UNIX:  <cy at FreeBSD.org>   Web:  http://www.FreeBSD.org

	The need of the many outweighs the greed of the few.