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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>,
        Kalle Valo <kvalo@qca.qualcomm.com>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.9 036/219] ath10k: fix fetching channel during
 potential radar detection
Thread-Topic: [PATCH AUTOSEL for 4.9 036/219] ath10k: fix fetching channel
 during potential radar detection
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Date:   Sat, 3 Mar 2018 22:28:16 +0000
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From: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>

[ Upstream commit a28f6f27a88f047f03f04b9246ca260ebc91455e ]

Fetch target operating channel during potential radar detection when
the interface is just brought up, but no channel is assigned from
userspace. In this scenario rx_channel may not be having a valid pointer
hence fetch the target operating channel to avoid warnings as below
which can be triggered by the commands with DFS testing over longer run

comamnds:
iw wlan1 set type mesh
ifconfig wlan1 up (valid tgt_oper_chan only)
iw wlan1 cac trigger freq 5260 HT20 (valid rx_channel, tgt_oper_chan)
iw wlan1 cac trigger freq 5280 HT20
iw wlan1 cac trigger freq 5300 HT20

Once the CAC expires, current channel context will be removed and
we are only left with the fallback option of using 'target operating
channel'

Firmware and driver log:
ath: phy1: DFS: radar found on freq=3D5300: id=3D1, pri=3D1125, count=3D5,
count_false=3D4
ath: phy1: DFS: radar found on freq=3D5260: id=3D5, pri=3D3151, count=3D6,
count_false=3D11
ath: phy1: DFS: radar found on freq=3D5280: id=3D1, pri=3D1351, count=3D6,
count_false=3D4
ath: phy1: DFS: radar found on freq=3D5300: id=3D1, pri=3D1125, count=3D5,
count_false=3D4
ath10k_pci 0001:01:00.0: failed to derive channel for radar pulse,
treating as radar
ath10k_pci 0001:01:00.0: failed to derive channel for radar pulse,
treating as radar

Call trace:

WARNING: CPU: 1 PID: 2145 at
backports-20161201-3.14.77-9ab3068/net/wireless/chan.c:265
cfg80211_set_dfs_state+0x3c/0x88 [cfg80211]()

 Workqueue: phy1 ieee80211_dfs_radar_detected_work
[mac80211]
[<c0320770>] (warn_slowpath_null) from [<bf79b90c>]
(cfg80211_set_dfs_state+0x3c/0x88 [cfg80211])
[<bf79b90c>] (cfg80211_set_dfs_state [cfg80211]) from
[<bf79697c>] (cfg80211_radar_event+0xc4/0x140 [cfg80211])
[<bf79697c>] (cfg80211_radar_event [cfg80211]) from
[<bf83c058>] (ieee80211_dfs_radar_detected_work+0xa8/0xb4 [mac80211])
[<bf83c058>] (ieee80211_dfs_radar_detected_work
[mac80211]) from [<c0339518>] (process_one_work+0x298/0x4a4)

Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/net/wireless/ath/ath10k/wmi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/wmi.c b/drivers/net/wireless/a=
th/ath10k/wmi.c
index 54df425bb0fc..e518b640aad0 100644
--- a/drivers/net/wireless/ath/ath10k/wmi.c
+++ b/drivers/net/wireless/ath/ath10k/wmi.c
@@ -3638,6 +3638,11 @@ static void ath10k_dfs_radar_report(struct ath10k *a=
r,
=20
 	spin_lock_bh(&ar->data_lock);
 	ch =3D ar->rx_channel;
+
+	/* fetch target operating channel during channel change */
+	if (!ch)
+		ch =3D ar->tgt_oper_chan;
+
 	spin_unlock_bh(&ar->data_lock);
=20
 	if (!ch) {
--=20
2.14.1