When auto channel selection (ACS) is used for HE 40MHz in 2.4GHz
band, AP sets center frequency after finding a 40MHz channel and
then runs a scan for overlapping BSSes in neighboring channels.
Upon OBSS detection, AP should downgrade to 20MHz bandwidth.
Currently this is broken because allowed_ht40_channel_pair() returns
true in this case and the steps to reset center frequency are not
executed causing failure to bring interface up.
Fix the condition to allow rollback to 20MHz.
Signed-off-by: Aloka Dixit <alokad@xxxxxxxxxxxxxx>
---
v3: Rebased to latest. Modified commit description.
src/ap/hw_features.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/ap/hw_features.c b/src/ap/hw_features.c
index f6e69030d767..1563a9ee34a4 100644
--- a/src/ap/hw_features.c
+++ b/src/ap/hw_features.c
@@ -313,7 +313,7 @@ static void ieee80211n_check_scan(struct hostapd_iface *iface)
{
struct wpa_scan_results *scan_res;
int oper40;
- int res;
+ int res = 0;
/* Check list of neighboring BSSes (from scan) to see whether 40 MHz is
* allowed per IEEE Std 802.11-2012, 10.15.3.2 */
@@ -349,7 +349,8 @@ static void ieee80211n_check_scan(struct hostapd_iface *iface)
}
}
- res = ieee80211n_allowed_ht40_channel_pair(iface);
+ if (iface->conf->secondary_channel)
+ res = ieee80211n_allowed_ht40_channel_pair(iface);
if (!res) {
iface->conf->secondary_channel = 0;
hostapd_set_oper_centr_freq_seg0_idx(iface->conf, 0);
base-commit: 88436baaac4172fda2abbe41449ff0bf8994ee9d
--
2.25.0
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