CFT: 11n support for iwn(4)

[Bernhard Schmidt]

On Sunday, May 01, 2011 23:36:56 Brandon Gooch wrote:
> On Sun, May 1, 2011 at 8:24 AM, Bernhard Schmidt <bschmidt at freebsd.org> wrote:
> > On Sunday 01 May 2011 13:19:30 Bernhard Schmidt wrote:
> >> Hi,
> >>
> >> I finally managed to get the 11n bits for iwn(4) sorted out. Well,
> >> there is still an issue somewhere with HT40 frame protection or
> >> TX chain setup on 5000 adapters, resulting in throughput not being
> >> that stable. But overall it seems to work pretty decently
> >>
> >> This is for HEAD only right now, net80211 in stable/8 does not yet
> >> contain the latest 11n related fixes. So, if you run HEAD and have
> >> some iwn(4) hardware, I'd appreciate feedback.
> >> ..
> >
> > Updated version, I've missed a locking issue.
> >
> > --
> > Bernhard
> 
> Thanks for working on this Bernhard!
> 
> Unfortunately, I'm having trouble achieving HT rates.
> 
> After 'wlandebug 0xffffffff', lots of:
> ...
> May  1 14:38:15 x300 kernel: wlan0: received beacon from
> 00:1d:0f:d3:fb:cc rssi 47
> May  1 14:38:15 x300 kernel: wlan0: [00:1d:0f:d3:fb:cc] discard beacon
> frame, ie too short, got 26, expected 30
> ...
> 
> I've attached relevant debugging information, but let me know if there
> may be anything else that could help. I need to work on DTracing
> net80211, any tips on relevant function traces?

Attachment seems to be missing?

I'd start of with enabling bootverbose to figure out if your adapter
supports 11n at all. There are some where the 11n bits have been
disabled. Next thing would be to check with
% ifconfig -v wlan0 list chan
if the HT channel setup works, if so it should list several HT20/HT40
channels. With
% wlanconfig +11n
you should at least see something like "Switching channel to HT20"
right before moving into RUN state. Also, does
% ifconfig wlan0 list scan
show HTCAP for the AP you're associating too?

-- 
Bernhard