Re: iwl4965 - wpa_supplicant can't see 5Ghz frequencies - 2.6.26-rc1 kernel

[Dan Williams <dcbw@redhat.com>]

On Thu, 2008-05-22 at 19:56 +0200, Johannes Berg wrote:
> >         memset(&iwe, 0, sizeof(iwe));
> >         iwe.cmd = SIOCGIWFREQ;
> > -       iwe.u.freq.m = bss->freq;
> > -       iwe.u.freq.e = 6;
> > +       iwe.u.freq.m = ieee80211_frequency_to_channel(bss->freq);
> > +       iwe.u.freq.e = 0;
> >         current_ev = iwe_stream_add_event(current_ev, end_buf, &iwe,
> >                                           IW_EV_FREQ_LEN);
> > 
> >         memset(&iwe, 0, sizeof(iwe));
> >         iwe.cmd = SIOCGIWFREQ;
> > -       iwe.u.freq.m = ieee80211_frequency_to_channel(bss->freq);
> > -       iwe.u.freq.e = 0;
> > +       iwe.u.freq.m = bss->freq;
> > +       iwe.u.freq.e = 6;
> >         current_ev = iwe_stream_add_event(current_ev, end_buf, &iwe,
> >                                           IW_EV_FREQ_LEN);
> 
> That doesn't make any sense, can you explain?

Explanation:

wpa_supplicant cannot handle A-band channel #s.  Thus, with the previous
code, the FREQ+frequency was sent first, and the FREQ+channel was sent
second.  Sending the FREQ+channel second made the supplicant overwrite
the value it already parsed from the FREQ+frequency for that BSSID.  But
since the supplicant can't handle A-band channel #s, you end up with 0.

Reversing the order of these two makes it work, but it's a total hack.
That may be what's needed right now though until everyone fixes their
supplicant.  There's overlap on A-band channels 7 - 12 (5035MHz ->
5060MHz) with B/G band channel #s.  Obviously WEXT falls over here
because the band isn't passed.

But what's the best fix to the supplicant?  It could just parse A-band
channels and where the numbers overlap, assume B/G band.  Or, it could
be patched to prefer FREQ+frequency over FREQ+channel if it received
both.  That's probably the best solution.

Dan