On 11/21/2016 03:04 PM, Benjamin Berg wrote:
> In the case that a spectral scan is enabled the PHY errors sent by the
> hardware as part of the scanning might trigger the radar detection and
> channels might be marked as 'unusable' incorrectly. This patch fixes
> the issue by preventing the spectral scan to be enabled if DFS is used
> and only analysing the PHY errors for DFS if radar detection is enabled.
>
> [...]
>From the relevant source code portion in channel.c:ath_set_channel()
80 /* Enable radar pulse detection if on a DFS channel. Spectral
81 * scanning and radar detection can not be used concurrently.
82 */
83 if (hw->conf.radar_enabled) {
84 u32 rxfilter;
85
86 rxfilter = ath9k_hw_getrxfilter(ah);
87 rxfilter |= ATH9K_RX_FILTER_PHYRADAR |
88 ATH9K_RX_FILTER_PHYERR;
89 ath9k_hw_setrxfilter(ah, rxfilter);
90 ath_dbg(common, DFS, "DFS enabled at freq %d\n",
91 chan->center_freq);
92 } else {
93 /* perform spectral scan if requested. */
94 if (test_bit(ATH_OP_SCANNING, &common->op_flags) &&
95 sc->spec_priv.spectral_mode == SPECTRAL_CHANSCAN)
96 ath9k_cmn_spectral_scan_trigger(common, &sc->spec_priv);
97 }
it seems that spectral can't ever be activated while operating on a DFS channel.
If you need to catch the opposite case, i.e. prevent feeding pseudo-radar pulses
into the pattern detector, you just need to ensure that they depend on
hw->conf.radar_enabled. A patch like the attached one should be enough.
Cheers,
Zefir
>From c24edf82e1f509490ba9dd3e34eec3ac3b309321 Mon Sep 17 00:00:00 2001
From: Zefir Kurtisi <zefir.kurtisi@xxxxxxxxxxx>
Date: Mon, 21 Nov 2016 15:33:45 +0100
Subject: [PATCH] ath9k: feed DFS detector only if operating on radar channel
---
drivers/net/wireless/ath/ath9k/recv.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 6697342..e4701a7 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -867,7 +867,8 @@ static int ath9k_rx_skb_preprocess(struct ath_softc *sc,
* can be dropped.
*/
if (rx_stats->rs_status & ATH9K_RXERR_PHY) {
- ath9k_dfs_process_phyerr(sc, hdr, rx_stats, rx_status->mactime);
+ if (hw->conf.radar_enabled)
+ ath9k_dfs_process_phyerr(sc, hdr, rx_stats, rx_status->mactime);
if (ath_cmn_process_fft(&sc->spec_priv, hdr, rx_stats, rx_status->mactime))
RX_STAT_INC(rx_spectral);
--
2.7.4
