TP Link Archer A6 V3 AP failed to configure in DFS channel

Hello Everyone ,

I have bought new TP-LINK Archer A6 V3.0 , and loaded 21.02.1 Openwrt firmware from this link https://firmware-selector.openwrt.org/?version=21.02.1&target=ramips%2Fmt7621&id=tplink_archer-a6-v3

ISSUE :- Failed to configure AP in DFS Channels , observing "hostapd: DFS start_dfs_cac() failed, -1" this error.

Mon Nov  8 11:48:30 2021 daemon.notice hostapd: wlan0: AP-ENABLED
Mon Nov  8 11:48:48 2021 daemon.notice hostapd: Configuration file: /var/run/hostapd-phy1.conf (phy wlan1) --> new PHY
Mon Nov  8 11:48:48 2021 daemon.notice hostapd: wlan1: interface state UNINITIALIZED->COUNTRY_UPDATE
Mon Nov  8 11:48:48 2021 daemon.notice hostapd: wlan1: interface state COUNTRY_UPDATE->HT_SCAN
Mon Nov  8 11:48:49 2021 daemon.notice hostapd: wlan1: interface state HT_SCAN->DFS
Mon Nov  8 11:48:49 2021 daemon.notice hostapd: wlan1: DFS-CAC-START freq=5580 chan=116 sec_chan=1, width=1, seg0=122, seg1=0, cac_time=60s
Mon Nov  8 11:48:49 2021 daemon.err hostapd: DFS start_dfs_cac() failed, -1
Mon Nov  8 11:48:49 2021 daemon.err hostapd: Interface initialization failed
Mon Nov  8 11:48:49 2021 daemon.notice hostapd: wlan1: interface state DFS->DISABLED
Mon Nov  8 11:48:49 2021 daemon.notice hostapd: wlan1: AP-DISABLED

Please help me with any solution to enable DFS channels??

might be relevant 5 GHz WLAN craps out (upon radar detection?) - start_dfs_cac() failed

No, the issue at play here is the mt76 driver lacks support for DFS on MT7613, see:

It's not looking good either, someone needs to implement it and it's not really a priority I reckon...

1 Like

Changing wireless country to "PA" in the Archer C6 v3.2 (same HW as the A6 v3) might be a temporary workaround and should enable the usage of DFS channels.

But I suspect this actually disables DFS scanning, which is not recommended and might be illegal depending on the country you live.

Thank you all , for your reply .

@dsouza , I verified with "PA" country code , able to configure DFS channels and STA connect successfully .

Also verified with TP Link Archer A6 V2 (ath79 chipset) with US country code itself , successfully able to configure all DFS channels and STA connection are stable.

Setting "PA" country in V3 model is temporary workaround and also not recommended, moving further can we get a support same as V2 model ?

completely different radio hardware - Qualcomm vs MediaTek.
down the road, who knows ....

As @frollic mentioned, the v2 and v3 are completely different hardwares. To have full DFS support for the v3 will depend on the development of the mt76 (Mediatek) Wi-Fi drivers.