David Young wrote:
> Are you using a MiniPCI or Cardbus ath(4) in your net4501?

Sorry, I totally forgot to provide this information. It is a PCI ath(4). 
Here is a picture of the construct:

http://www.smokva.net/img/net4501.jpg


>>#ifconfig ath0 up chan 7 media OFDM54 mode 11g mediaopt adhoc ssid 
>>TESTNETZ 130.92.178.20 netmask 255.255.255.0 broadcast 130.92.178.255
> 
> 
> I can reproduce this.  In
> sys/net80211/ieee80211_netbsd.c:ieee80211_getmgtframe, see if it helps
> to change the line
> 
>         if (len < MINCLSIZE) {
> [...]

The page-faults are gone, nice! But unfortunately not the 'reset'-error. 
The simple ifconfig-command:

#ifconfig ath0 up

lets the kernel print out the following lines:

ath0: link state changed to UP
ath0: device timeout
ath0: ath_reset: unable to reset hardware; hal status 0

Another interesting behaviour is about the two light-emitting diodes 
next to the antenna-connector (see picture). Straight after the boot 
(login), just the diode below glows. After 'ifconfig ath0 up' both start 
to blink - together, continued and regular.

BTW: You can't put the card back into the 'one-glows-only'-mode with 
'ifconfig ath0 down' because: "unable to reset hardware".


 > Is there any difference if you use a NET4501 kernel?

I don't believe so. There are the same 'reset'-errors like with 
GENERIC_LAPTOP.


With kind regards,

Petar