hostapd config for 802.11ac failing

[v lakshmi]

Hi,

I am trying to setup an Access point using hostapd in 802.11ac mode.

The wireless interface pcie device supports 80MHz channel.
I verified that with "iw list".

When I configure it in 5 Ghz mode, it works fine.

When I configure vht_oper_chwidth=1 and then I get the error as

ACS: Failed to get compute ideal channel.
ACS: Possibly channel configuration is invalid, pls report this along with your config file.

Here is the hostapd.conf that I am using 

interface=wlan1
driver=nl80211
hw_mode=a
ssid=test1234

ieee80211n=1
ht_capab=[HT40+][LDPC][SHORT- GI-20][SHORT-GI-40][TX-STBC][ RX-STBC-1]

ieee80211ac=1
vht_oper_chwidth=1
vht_oper_centr_freq_seg0_idx= 42
vht_capab=[MAX-MPDU-11454][ RXLDPC][SHORT-GI-80][TX-STBC]
wmm_enabled=1
wme_enabled=1
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_passphrase=test1234

Thanks for any help,
vijaya