Failed to start radar detection: -22 (Invalid argument)

[Jeremias Blendin]

Hi,

I am having issues to get a ath10k wifi card working and I did not
find any information on the -22 error code:

HT40: control channel: 52  secondary channel: 56
Completing interface initialization
Mode: IEEE 802.11a  Channel: 52  Frequency: 5260 MHz
DFS 4 channels required radar detection
DFS all channels available, (SKIP CAC): no
DFS 0 chans unavailable - choose other channel: no
wlan1: interface state HT_SCAN->DFS
DFS start CAC on 5260 MHz
wlan1: DFS-CAC-START freq=5260 chan=52 sec_chan=1, width=1, seg0=58,
seg1=0, cac_time=60s
nl80211: Start radar detection (CAC) 5260 MHz (ht_enabled=1,
vht_enabled=1, bandwidth=80 MHz, cf1=5290 MHz, cf2=0 MHz)
nl80211: Failed to start radar detection: -22 (Invalid argument)
DFS start_dfs_cac() failed, -1
Interface initialization failed
wlan1: interface state DFS->DISABLED
wlan1: AP-DISABLED
....

System information:
Linux kyushu 3.16.0-29-generic #39-Ubuntu SMP Mon Dec 15 22:27:29 UTC
2014 x86_64 x86_64 x86_64 GNU/Linux
Firmware:
[   15.060828] ath10k: pci irq MSI irq_mode 0 reset_mode 0
[   16.919940] ath10k: qca988x hw2.0 (0x4100016c, 0x043202ff) fw
10.1.467.2-1 api 2 htt 2.1
Country:
iw reg get
country DE: DFS-UNSET
(2400 - 2483 @ 40), (N/A, 20)
(5150 - 5250 @ 80), (N/A, 20), NO-OUTDOOR
(5250 - 5350 @ 80), (N/A, 20), NO-OUTDOOR, DFS
(5470 - 5725 @ 80), (N/A, 26), DFS
(57240 - 65880 @ 2160), (N/A, 40), NO-OUTDOOR

Any ideas what could be the issue?

Jeremias