I've been using STA+AP modes at home for a couple years now
and I've been finding and fixing a lot of weird corner cases.
This is the eventual patchset I've landed on.
* Don't force beacon resync in STA mode if we're using sw beacon tracking.
This stops a variety of stomping issues when the STA VAP is reconfigured;
the AP hardware beacons were being stomped on!
* Use the first AP VAP to configure beacons on, rather than the first VAP.
This prevents weird behaviour in ath_beacon_config() when the hardware
is being reconfigured and the STA VAP was the first one created.
* Ensure the beacon interval / timing programming is within the AR9300
HAL bounds by masking off any flags that may have been there before
shifting the value up to 1/8 TUs rather than the 1 TU resolution the
previous chips used.
Now I don't get weird beacon reprogramming during startup, STA state
changes and hardware recovery which showed up as HI-LARIOUS beacon
configurations and STAs that would just disconnect from the AP very
frequently.
Tested:
* AR9344/AR9380, STA and AP and STA+AP modes