Failed to set channel for kernel driver

[Michal Kazior]

On 4 February 2016 at 13:26, Matthew Keeler <mjkeeler7 at gmail.com> 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