Trying to start hostapd fails if channel is set to 'auto' in UCI resulting in channel=acs_survey ending up in hostapd.conf.
Configuration file: /var/run/hostapd-phy0.conf
wlan0: interface state UNINITIALIZED->COUNTRY_UPDATE
ACS: Automatic channel selection started, this may take a bit
wlan0: interface state COUNTRY_UPDATE->ACS
wlan0: ACS-STARTED
ACS: Unable to collect survey data
ACS: All study options have failed
Interface initialization failed
wlan0: interface state ACS->DISABLED
wlan0: AP-DISABLED
ACS: Possibly channel configuration is invalid, please report this along with your config file.
ACS: Failed to start
wlan0: AP-DISABLED
hostapd_free_hapd_data: Interface wlan0 wasn't started
nl80211: deinit ifname=wlan0 disabled_11b_rates=0
wlan0: interface state DISABLED->DISABLED
wlan0: interface state DISABLED->DISABLED
wlan0: AP-DISABLED
hostapd_free_hapd_data: Interface wlan0 wasn't started
auto-generated configuration:
driver=nl80211
logger_syslog=127
logger_syslog_level=2
logger_stdout=127
logger_stdout_level=2
country_code=DE
ieee80211d=1
ieee80211h=1
hw_mode=a
channel=acs_survey
ieee80211n=1
ht_coex=0
ht_capab=[HT40+][LDPC][SHORT-GI-20][SHORT-GI-40][TX-STBC][RX-STBC1]
vht_oper_chwidth=1
vht_oper_centr_freq_seg0_idx=-6
ieee80211ac=1
vht_capab=[RXLDPC][SHORT-GI-80][TX-STBC-2BY1][RX-STBC-1][MAX-A-MPDU-LEN-EXP0]
interface=wlan0
ctrl_interface=/var/run/hostapd
ap_isolate=1
disassoc_low_ack=1
preamble=1
wmm_enabled=1
ignore_broadcast_ssid=0
uapsd_advertisement_enabled=1
wpa_passphrase=topsecretpassword
auth_algs=1
wpa=2
wpa_pairwise=CCMP
ssid=OpenWrt
bridge=br-lan
wpa_key_mgmt=WPA-PSK
okc=0
disable_pmksa_caching=1
bssid=78:a3:51:0d:12:f5