setting channel in ad-hoc and managed

[Giulio Orsero]

====== wvlan_cs.c:

// Set frequency/channel
                case SIOCSIWFREQ:
...
...
  if (((local->port_type != 3) && (!local->allow_ibss))  <============
                   || (wrq->u.freq.m > 1000) || (wrq->u.freq.e > 0))
                               rc = -EOPNOTSUPP;
=======
Can you explain the meaning?

When trying to set channel to 1 in managed modem my values are:
port_type: 1 , wrq->u.freq.m: 1, wrq->u.freq.e: 0, allow_ibss: 0

When I am allowed to set the channel?
If I'm in ad-hoc mode, fine. If I'm in managed mode I need allow_ibss=1?
When I load wvlan_cs with allow_ibss=1 I'm told my firmware (6.04) does not
support it.

I'm interested in the teorical reason for this limitation. Reading the
driver I only find IBSS in the IBSS-Ad-hoc mode, so what has it to do with
managed mode?

Is it that if a wireless client is in managed mode then it cannot set the
channel because it has to use whatever the AP is using? If there are 2 APs
with 2 channels how I can use one or the other?

My cards are buffalo/melco. If I want to update the firmware, can I use the
one provided by orinoco/lucent, or should I only use one provided by melco?

Thanks

-- 
giulioo at pobox.com