Failed to set channel for kernel driver

[Matthew Keeler]

You were correct about the card not supporting radar detection. As I was gathering info for the other things you suggested I got it to work. The main problems (other than not using DFS) were having my test configuration not provide the ht_capab and vht_capab config parameters and having vht_oper_centr_freq* params set. Adding the capabilities and removing the  vht frequency specification got it working.

One related question I have is why hostapd can’t figure out the capabilities on its own. In the debug output there is a line telling me what the card is advertising and what was set in the configuration. If it knows what the card is advertising why can’t it use that by default?


--  
Matt Keeler


On February 4, 2016 at 07:37:03, Michal Kazior (michal.kazior at tieto.com(mailto:michal.kazior at tieto.com)) wrote:

> On 4 February 2016 at 13:26, Matthew Keeler wrote:
> >
> > I have been trying a few different things to get hostapd working with my wireless card. With ieee80211d/h off ACS attempts to use channel 149 (80 MHz wide) and prints out a message of "Could not set channel for kernel driver”.
>  
> Are you sure your regulatory allows it? The channel must *not* have
> NO-IR flag set on it. If it does you can't initiate radiation on it
> (i.e. no AP).
>  
> Check your regulatory: iw reg get
> And your channel list with: iw list
>  
> You may have an old regulatory database, broken CRDA setup or simply
> have a card which has world-roaming regulatory baked in EEPROM. See
> ath10k infradead mailing list archives, please. A similar problem has
> been recently discussed.
>  
>  
> > When I turn ieee80211d/h on the message I get is "Can't set freq params” and "DFS start_dfs_cac() failed, -1”. The DFS stuff seems to want to use channel 52. According to iw list both 52 and 149 are supported channels by my hardware.
>  
> 52 will need radar detection. This in turns requires regulatory opus
> to be configured at kernel/backports compile time. You can check `iw
> list` to see if your instance of ath10k advertises radar detection in
> interface combinations. It most likely doesn't which explains the
> warning above.
>  
>  
> >
> > I am using the ath10k driver with a Airetos AEX-QCA9880-NX wireless card. The full testing configuration I am attempting to use is below. Is there anything I am completely wrong on or could there be driver/firmware/hardware issues?
> >
> > interface=lan-wireless
> > driver=nl80211
> > ssid=test
> > hw_mode=a
> > channel=0
> > ieee80211n=1
> > ieee80211ac=1
> > ieee80211d=0
> > ieee80211h=0
> > country_code=US
> > vht_oper_chwidth=1
> > vht_oper_centr_freq_seg0_idx=42
> > vht_oper_centr_freq_seg1_idx=159
>  
> seg0/seg1 are supposed to be used both only for 80+80. QCA9880 doesn't
> support it. It only makes sense to set seg0 for 80Mhz.
>  
> But since you're setting channel=0 (requesting ACS) the seg0 will be
> overwritten/disregarded anyway.
>  
>  
> Michał