Return-path: Received: from wolverine02.qualcomm.com ([199.106.114.251]:49433 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751248AbaLOXj1 (ORCPT ); Mon, 15 Dec 2014 18:39:27 -0500 Message-ID: <548F7101.7060602@qca.qualcomm.com> (sfid-20141216_003931_102311_5C686327) Date: Mon, 15 Dec 2014 15:38:41 -0800 From: Peter Oh MIME-Version: 1.0 To: Felix Fietkau , CC: Subject: Re: [PATCH] ath: fix incorrect PPB on FCC radar type 5 References: <1418669734-12921-1-git-send-email-poh@qca.qualcomm.com> <548F47D1.8080502@openwrt.org> In-Reply-To: <548F47D1.8080502@openwrt.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/15/2014 12:42 PM, Felix Fietkau wrote: > On 2014-12-15 19:55, Peter Oh wrote: >> The minimum number of pulses per burst on FCC radar type 5 is 1. >> Use this number for correct radar detection. >> >> Signed-off-by: Peter Oh >> --- >> drivers/net/wireless/ath/dfs_pattern_detector.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/wireless/ath/dfs_pattern_detector.c b/drivers/net/wireless/ath/dfs_pattern_detector.c >> index cfd0554..3d57f87 100644 >> --- a/drivers/net/wireless/ath/dfs_pattern_detector.c >> +++ b/drivers/net/wireless/ath/dfs_pattern_detector.c >> @@ -86,7 +86,7 @@ static const struct radar_detector_specs fcc_radar_ref_types[] = { >> FCC_PATTERN(1, 0, 5, 150, 230, 1, 23), >> FCC_PATTERN(2, 6, 10, 200, 500, 1, 16), >> FCC_PATTERN(3, 11, 20, 200, 500, 1, 12), >> - FCC_PATTERN(4, 50, 100, 1000, 2000, 1, 20), >> + FCC_PATTERN(4, 50, 100, 1000, 2000, 1, 1), > Won't that significantly increase the false positive rate? No. FCC type 5 radar's PPB is in between 1~3 and DFS simulators such as VeriWave machine pick one among the number (typically 1), hence to detect the type 5 radar we should pick the minimum number which is 1 unless we won't detect the radar if pulse comes only once. > Here's the previous change on that pattern: Actually their assumption (?) on FCC is incorrect. PPB and PRF was not interchanged, the previous parameters simply picked wrong PRF for FCC instead (FCC type 5 radar's PRF is 1). For Japan those parameters look quite different from what I've seen from Japan's Communications Ministry (MIC, www.tele.soumu.go.jp/e/sys/equ/tech/5ghz/5ghz.htm), but I couldn't say if it's correct or not at this moment since I haven't run DFS on Japan yet. > commit 562930f8baee7a1cb5b9f382b4338c9b6fbf1139 > Author: Vivek Natarajan > Date: Mon Nov 24 17:26:22 2014 +0530 > > ath: Fix a false radar detection pattern > > For FCC and JP, in one of the radar patterns, PPB and PRF seems to be > interchanged leading to frequent incorrect radar detections. > > Signed-off-by: Vivek Natarajan > Signed-off-by: John W. Linville > > diff --git a/drivers/net/wireless/ath/dfs_pattern_detector.c b/drivers/net/wireless/ath/dfs_pattern_detector.c > index 650be79..cfd0554 100644 > --- a/drivers/net/wireless/ath/dfs_pattern_detector.c > +++ b/drivers/net/wireless/ath/dfs_pattern_detector.c > @@ -86,7 +86,7 @@ static const struct radar_detector_specs fcc_radar_ref_types[] = { > FCC_PATTERN(1, 0, 5, 150, 230, 1, 23), > FCC_PATTERN(2, 6, 10, 200, 500, 1, 16), > FCC_PATTERN(3, 11, 20, 200, 500, 1, 12), > - FCC_PATTERN(4, 50, 100, 1000, 2000, 20, 1), > + FCC_PATTERN(4, 50, 100, 1000, 2000, 1, 20), > FCC_PATTERN(5, 0, 1, 333, 333, 1, 9), > }; > > @@ -105,7 +105,7 @@ static const struct radar_detector_specs jp_radar_ref_types[] = { > JP_PATTERN(4, 0, 5, 150, 230, 1, 23), > JP_PATTERN(5, 6, 10, 200, 500, 1, 16), > JP_PATTERN(6, 11, 20, 200, 500, 1, 12), > - JP_PATTERN(7, 50, 100, 1000, 2000, 20, 1), > + JP_PATTERN(7, 50, 100, 1000, 2000, 1, 20), > JP_PATTERN(5, 0, 1, 333, 333, 1, 9), > };