Could not select hw_mode and channel. (-3)

Michal Kazior michal.kazior
Thu Nov 20 00:02:33 PST 2014

On 19 November 2014 23:59, Lasse Jensen <and0806 at> wrote:
> Hi List
> I have a problem with my hostapd setup.
> I got a Sparklan WPEA-352ACN 802.11ac/b/g/n Mini Card, Qualcomm Atheros QCA9880-BR4A
> and i want to use the 802.11ac speed but i only got 4 usable channels in the 5Ghz area, channel
> 36, 40, 44, 48. If i try to use a channel between 52 and 165 i get this:
>   [root at localhost ~]# hostapd /etc/hostapd/hostapd.conf
>   Configuration file: /etc/hostapd/hostapd.conf
>   wlp1s0: interface state UNINITIALIZED->COUNTRY_UPDATE
>   wlp1s0: IEEE 802.11 Configured channel (64) not found from the channel list of current mode (2) IEEE 802.11a
>   wlp1s0: IEEE 802.11 Hardware does not support configured channel
>   Could not select hw_mode and channel. (-3)
>   wlp1s0: interface state COUNTRY_UPDATE->DISABLED
>   wlp1s0: AP-DISABLED
>   wlp1s0: Unable to setup interface.
>   hostapd_free_hapd_data: Interface wlp1s0 wasn't started
> same thing if i try to enable 40 or 80 MHz channel width,

Are you aware how 11ac channel definition should be set up in hostap?

E.g. if you want to use channels 36 (primary) and 40 (secondary) for
VHT40 you need to have:

(I'm writing this from memory)

> I have used hostapd v2.3 and v2.4-devel with kernel 3.17.2 and i have tested all the firmware images for the ath10k modul
> I think it has something to do with my reg domain "DK" and the DFS options in the driver, but i can?t figure it out?
> I have read that there is a module option "Atheros DFS support for certified platforms" in some kernel,
> but i don?t have that compile build option in my menuconfig in kernel 3.17.2?

Before you can enable ATH10K_DFS_CERTIFIED you must enable
CFG80211_CERTIFICATION_ONUS (this has some legal

Anyway 11ac performance on DFS channels will most likely be inferior
compared to non-DFS channels because hw has to watch out for radar
pulses on DFS channels.

>   [root at localhost ~]# iw reg get
>   country DK: DFS-UNSET
>           (2402 - 2482 @ 40), (N/A, 20)
>           (5170 - 5250 @ 40), (N/A, 20)

Your regulatory doesn't allow you to run at more than 40MHz. This
means you can't run 11ac @ 80MHz. You should be able to run 11ac @
40MHz though.

>           (5250 - 5330 @ 40), (N/A, 20), DFS
>           (5490 - 5710 @ 40), (N/A, 27), DFS
>           (57240 - 65880 @ 2160), (N/A, 40), NO-OUTDOOR
> DFS-UNSET?? what??

You either have an outdated regulatory database or there was an
intersection and the DFS region came out ambiguous. Intersection can
happen if you have 2 different wifi cards in your system and/or you
set user country code.

The latter may be the case here because QCA988X is most likely US (FCC
DFS region) and you set DK (ETSI DFS region).

> Can some one tell me a little about this... or point me in the right direction, show me were I go wrong.
> I want real 802.11ac speed and i can only get every thing to play nice at 2,4Ghz under 802.11n speed and 802.11b/g but i got this QCA9880 to get the full 802.11ac 3x3 speed.

You should investigate (and possibly fix) your regulatory
configuration. See:


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