Autodetecting HT capabilities?

[Ed W]

Hi, I have a scenario where I want to support a generic hostapd.conf, 
but for a selection of mini pci cards with varying capabilities

I hit a problem where enabling:
     ieee80211n=1
or
     ieee80211ac=1

Stops hostapd 2.4 starting up for two of my cards: WLM54AGP23 and 
DCMA-81, neither of which claims to support HT40 in "iw list" (but I 
would prefer hostapd ignore and continue rather than failing to start)

Specific errors I get are (kernel 3.15.10):

hw vht capab: 0x0, conf vht capab: 0x0
Completing interface initialization
Mode: IEEE 802.11g  Channel: 1  Frequency: 2412 MHz
DFS 0 channels required radar detection
nl80211: Set freq 2412 (ht_enabled=1, vht_enabled=0, bandwidth=20 MHz, 
cf1=2412 MHz, cf2=0 MHz)
   * freq=2412
   * vht_enabled=0
   * ht_enabled=1
   * sec_channel_offset=0
   * channel_type=1
nl80211: Failed to set channel (freq=2412): -22 (Invalid argument)
Could not set channel for kernel driver
Interface initialization failed
wlan0: interface state UNINITIALIZED->DISABLED



So first question is *should* hostapd v2.4 be able to autodetect lack of 
capability of the card and ignore the n/ac directives?

If it should not, is it a feature request which can be reasonably presented?

Failing all of the above, how do others manage autoconfiguration in such 
a case?


Thanks for your thoughts

Ed W