since the HAL 2008-08-15, the frequency usage is strictly limited in an uncomfortable way that prevents using new HAL in scenarios when one card is configured to receive at outdoor 5GHz frequencies and the second card is transmitting at indoor 5GHz frequencies (e.g. Local indoor 5GHz AP receiving connectivity from outdoor 5GHz long-distance link). With the HAL 2008-05-28 everything works as expected. Managed mode card receives at outdoor frequencies 5.5-5.7 GHz and master mode indoor AP transmits at indoor frequency 5.26 GHz. This is for countrycode=276. With the new HAL When you modprobe ath_pci with countrycode=276 without outdoor parameter, only indoor frequencies are available and therefore Managed mode card is not able to connect to the outdoor AP. With outdoor=1, we must use outdoor frequency for indoor local AP thus wasting frequency spectrum by not using frequencies available for indoor
5GHz. Nevertheless there is a risk of overlaping two outdoor frequencies since the outdoor incoming link can switch frequency randomly.
The solution would be to preserve-restore the behavior of the old HAL to allow automatic indoor/outdoor frequencies available simultaneously and remove outdoor module parameter or introduce a sysctl parameter which is able to change the frequency range (indoor/outdoor usage) of a card on-the-fly.
The cards used in this scenario are Wistron CM9 cards (AR5213).
The other cards (Mikrotik R52 - AR5414) have also been tested.