Commit 96ff5641 authored by Johannes Berg's avatar Johannes Berg Committed by Reinette Chatre

iwlwifi: work around passive scan issue

Some firmware versions don't behave properly when
passive scanning is requested on radar channels
without enabling active scanning on receiving a
good frame. Work around that issue by asking the
firmware to only enable the active scanning after
receiving a huge number of good frames, a number
that can never be reached during our dwell time.
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarReinette Chatre <reinette.chatre@intel.com>
parent 0250ecec
......@@ -2621,7 +2621,9 @@ struct iwl_ssid_ie {
#define PROBE_OPTION_MAX_3945 4
#define PROBE_OPTION_MAX 20
#define TX_CMD_LIFE_TIME_INFINITE cpu_to_le32(0xFFFFFFFF)
#define IWL_GOOD_CRC_TH cpu_to_le16(1)
#define IWL_GOOD_CRC_TH_DISABLED 0
#define IWL_GOOD_CRC_TH_DEFAULT cpu_to_le16(1)
#define IWL_GOOD_CRC_TH_NEVER cpu_to_le16(0xffff)
#define IWL_MAX_SCAN_SIZE 1024
#define IWL_MAX_CMD_SIZE 4096
#define IWL_MAX_PROBE_REQUEST 200
......
......@@ -812,16 +812,29 @@ static void iwl_bg_request_scan(struct work_struct *data)
rate = IWL_RATE_1M_PLCP;
rate_flags = RATE_MCS_CCK_MSK;
}
scan->good_CRC_th = 0;
scan->good_CRC_th = IWL_GOOD_CRC_TH_DISABLED;
} else if (priv->scan_bands & BIT(IEEE80211_BAND_5GHZ)) {
band = IEEE80211_BAND_5GHZ;
rate = IWL_RATE_6M_PLCP;
/*
* If active scaning is requested but a certain channel
* is marked passive, we can do active scanning if we
* detect transmissions.
* If active scanning is requested but a certain channel is
* marked passive, we can do active scanning if we detect
* transmissions.
*
* There is an issue with some firmware versions that triggers
* a sysassert on a "good CRC threshold" of zero (== disabled),
* on a radar channel even though this means that we should NOT
* send probes.
*
* The "good CRC threshold" is the number of frames that we
* need to receive during our dwell time on a channel before
* sending out probes -- setting this to a huge value will
* mean we never reach it, but at the same time work around
* the aforementioned issue. Thus use IWL_GOOD_CRC_TH_NEVER
* here instead of IWL_GOOD_CRC_TH_DISABLED.
*/
scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH : 0;
scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
IWL_GOOD_CRC_TH_NEVER;
/* Force use of chains B and C (0x6) for scan Rx for 4965
* Avoid A (0x1) because of its off-channel reception on A-band.
......
......@@ -2966,7 +2966,8 @@ static void iwl3945_bg_request_scan(struct work_struct *data)
* is marked passive, we can do active scanning if we
* detect transmissions.
*/
scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH : 0;
scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
IWL_GOOD_CRC_TH_DISABLED;
band = IEEE80211_BAND_5GHZ;
} else {
IWL_WARN(priv, "Invalid scan band count\n");
......
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