Atheros DFS radar detection

[Wright, Brett]

Hi Adrian,

> -----Original Message-----
> From: adrian.chadd at gmail.com [mailto:adrian.chadd at gmail.com] On Behalf
> Of Adrian Chadd
> Sent: Wednesday, 1 August 2012 1:23 PM
> Which source? The stuff in madwifi-dfs? or elsewhere?

Yes madwifi-dfs. 

> Which radar configuration parameters are you using?
> I'd first start by looking at the radar parameters that you're using.
> What are they?

I think this is the standard setup for DFS, firstly setup the rx filter
for phy radar errors (am not using interference mitigation so
HAL_RX_FILTER_PHYERR is not set):

	rfilt |= HAL_RX_FILTER_PHYRADAR;
	ath_hal_setrxfilter(ah, rfilt);

Then in the rx interrupt check for radar pulses:

	if ((HAL_RXERR_PHY == rs->rs_status) &&
	    (HAL_PHYERR_RADAR == (rs->rs_phyerr & 0x1f)) &&
	    !(bf->bf_status & ATH_BUFSTATUS_RADAR_DONE) &&
	    (ic->ic_flags & IEEE80211_F_DOTH))
		check_for_radar = 1;

And then these pulses are analyzed and potentially matched to the
required radar patterns...
The problem as I see it is that I get these phy radar errors even when
the only thing going on is valid (i.e. crc error free data). There is no
other RF noise around, I can even do the test with coax and attenuators
between my two modules. I only get the "false pulse" phy radar errors
when I am transferring data between my pair of modules under test. 

Thanks
Brett