HE: Fall back to 20 MHz on 2.4 GHz if 40 MHz is not supported

At least the ACS case of an attempt to pick a 40 MHz channel on the 2.4
GHz band could fail if HE was enabled and the driver did not include
support for 40 MHz channel bandwidth on the 2.4 GHz band in HE
capabilities. This resulted in "40 MHz channel width is not supported in
2.4 GHz" message when trying to configure the channel and failure to
start the AP.

Avoid this by automatically falling back to using 20 MHz bandwidth as
part of channel parameter determination at the end of the ACS procedure.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

diff --git a/src/ap/hw_features.c b/src/ap/hw_features.c
index 93d19e0ba419dee9ae6e27510d2b3d8a29dc2207..7849be181c212d6fb68c14d25a149e8f432ac892 100644 (file)
--- a/src/ap/hw_features.c
+++ b/src/ap/hw_features.c
@@ -349,6 +349,22 @@ static void ieee80211n_check_scan(struct hostapd_iface *iface)
                }
        }
 
+#ifdef CONFIG_IEEE80211AX
+       if (iface->conf->secondary_channel &&
+           iface->current_mode->mode == HOSTAPD_MODE_IEEE80211G &&
+           iface->conf->ieee80211ax) {
+               struct he_capabilities *he_cap;
+
+               he_cap = &iface->current_mode->he_capab[IEEE80211_MODE_AP];
+               if (!(he_cap->phy_cap[HE_PHYCAP_CHANNEL_WIDTH_SET_IDX] &
+                     HE_PHYCAP_CHANNEL_WIDTH_SET_40MHZ_IN_2G)) {
+                       wpa_printf(MSG_DEBUG,
+                                  "HE: 40 MHz channel width is not supported in 2.4 GHz; clear secondary channel configuration");
+                       iface->conf->secondary_channel = 0;
+               }
+       }
+#endif /* CONFIG_IEEE80211AX */
+
        if (iface->conf->secondary_channel)
                res = ieee80211n_allowed_ht40_channel_pair(iface);
        if (!res) {