I'm not sure this will help anything, but just FYI:

We've noticed a problem with the TX power on several ath-based cards. We 
have a spectrum analyzer hooked directly up to the antenna, and are 
measuring the output as we bring up the interface (with a modprobe then 
ifup) and start a flood ping. In this case we're testing 802.11g on 
channel 2.

We get a beautiful strong hump at 2.417 ghz. I do a:

athdebug -i ath1 +reset +beacon +watchdog +calibrate +state +node +fatal
tail -f /var/log/messages

30 seconds later we get a calibration message. 30 seconds after that we 
get another calibration message and driver decides rfgain is out of 
bounds and we need to reset (comments removed):

     if (ath_hal_getrfgain(ah) == HAL_RFGAIN_NEED_CHANGE) {
         sc->sc_stats.ast_per_rfgain++;
         ath_reset(dev);
     }

At this point the signal strength drops about 10db. And _never comes 
back_. Nothing we do can convince it to return to full power, including 
the usual poking with the sysctl settings or 'resetting' it by setting 
the essid again. I added a ath_update_txpow() at the end of the reset 
routine in case it was a race condition, and even added a force 
parameter to the function so it wouldn't do the 'if we still think it's 
equal don't really set it' check.

ifdown/ifup does nothing. But! if I rmmod the drivers then modprobe and 
ifup again it's happy (full power). Until 60 seconds later when it 
calibrates again...

The real kicker is that not even all the cards from the same mfr show 
this problem. It's consistent if we put the cards in other boxes. The 
'bad' ones are still bad. 3 of 4 of the cards we've tested for one mfr 
show this problem (and we have other cards in the field definitely 
showing this issue). For another, 0 of 2.

We're not sure right now if this is a card firmware version issue or 
what else it might be, but I thought it might be useful data for your 
power concerns.

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