Unable to set wifi channel to auto

Installing and Using OpenWrt Network and Wireless Configuration
1

If I set my channel to auto the wifi does not appear to come up.
The icon does not turn blue.
wifi%201

Why am I unable to use auto?

Here are more details about my device and configuratation
Model: Netgear R8000 (BCM4709)
Architecture: ARMv7 Processor rev 0 (v7l)
Firmware Version: OpenWrt 18.06.2 r7676-cddd7b4c77 / LuCI openwrt-18.06 branch (git-19.020.41695-6f6641d)
Kernel Version: 4.14.95

[/etc/config/wireless]
config wifi-device 'radio0'
option type 'mac80211'
option hwmode '11a'
option path '18000000.axi/bcma0:7/pci0000:00/0000:00:00.0/0000:01:00.0'
option htmode 'VHT80'
option legacy_rates '1'
option channel '149'
option country 'US'

config wifi-iface 'default_radio0'
option device 'radio0'
option mode 'ap'
option network 'lan'
option encryption 'psk2'
option key '<my_key>'
option ssid 'CyberRange'
option hidden '1'

config wifi-device 'radio1'
option type 'mac80211'
option channel '11'
option hwmode '11g'
option path '18000000.axi/bcma0:8/pci0001:00/0001:00:00.0/0001:01:00.0/0001:02:01.0/0001:03:00.0'
option htmode 'HT20'
option country 'US'
option legacy_rates '1'

config wifi-iface 'default_radio1'
option device 'radio1'
option mode 'ap'
option network 'lan'
option encryption 'psk2'
option key '<my_key>'
option ssid 'CyberRange'
option hidden '1'

config wifi-device 'radio2'
option type 'mac80211'
option channel '36'
option hwmode '11a'
option path '18000000.axi/bcma0:8/pci0001:00/0001:00:00.0/0001:01:00.0/0001:02:02.0/0001:04:00.0'
option htmode 'VHT80'
option country 'US'
option legacy_rates '1'

config wifi-iface 'default_radio2'
option device 'radio2'
option mode 'ap'
option network 'lan'
option encryption 'psk2'
option key '<my_key>'
option ssid 'CyberRange'
option hidden '1'

As you can see this is a multi radio device. If I remember correctly I can set at least one or maybe two of the three configs to auto but no all three. I'd need to test further to see which combinations might work. Before I try various combinations I thought I'd reach out to see if anyone had ideas based on the info I provided above. I hate to chase down the wrong rabbit hole and I'm glad to provide more info as needed. Thanks!

2

Channel "Auto" in OpenWrt doesn't actually do anything automatic. It just selects the first channel in the list. So there's no reason to select "Auto".

The R8000 has Broadcom wifi chips and thus very incomplete wifi support.

2 Likes
3

Ok, does auto have a function at all or is that dependent upon the chipset you have in the device? So if it selects the first channel why wouldn't the device come up?

4

Auto does need kernel (driver) support (ACS) and it does have a function, namely to always set a valid (not a good one, just a valid one) channel regardless of the wlan card or the regdomain it's operating under. The gist of its functionality is to look at all constraints (which band and sub-band does the card adhere to, what regdom is configured) and then to pick the first channel within those, it doesn't do anything smarter beyond that - always the first valid channel. You are supposed to pick a better one based on your local distribution of bssids yourself.

2 Likes
5

Thanks for providing additional clarification. That makes sense. It didn't make sense to me why picking auto didn't allow the device to come up properly because in theory that should have worked.. However, given the scenario and parameters described by everyone on this thread it seems the simplest course of action is to manually choose a chanel. FWIW- I had origianlly thought that choosing auto somehow allowd the wireless to change channels as needed depending on the environment it was placed int. Sort of a smart device that can adjsut itself. I can tell very clearly now that the setting is "dumb". Thanks all!