This in particular fixes radar PHY handling - on the AR5212
NIC, one enables the AR_PHY_ERR_RADAR bit in AR_PHY_ERR;
the AR5416 and later also needs a bit set in AR_RX_FILTER.
A follow-up commit is needed to convert the AR5416 ANI code
to use this particular method, as it's currently using the
AR5212 methods directly.
Obtained from: Atheros
Approved by: re (kib)
From the ath9k source:
==
11N: we can no longer afford to self link the last descriptor.
MAC acknowledges BA status as long as it copies frames to host
buffer (or rx fifo). This can incorrectly acknowledge packets
to a sender if last desc is self-linked.
==
Since this is useful for pre-AR5416 chips that communicate PHY errors
via error frames rather than by on-chip counters, leave the support
in there, but disable it for AR5416 and later.
