Wifi connection on Linux

I installed a PCIe wifi to Apalis i.MX6D with Linux. The device and interface can be accessed.

root@apalis-imx6:~# ifconfig
wlp4s0    Link encap:Ethernet  HWaddr 20:7C:8F:56:BC:DE  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

root@apalis-imx6:~# lspci
00:00.0 PCI bridge: Synopsys, Inc. Device abcd (rev 01)
01:00.0 PCI bridge: PLX Technology, Inc. PEX 8605 PCI Express 4-port Gen2 Switch (rev aa)
02:01.0 PCI bridge: PLX Technology, Inc. PEX 8605 PCI Express 4-port Gen2 Switch (rev aa)
02:02.0 PCI bridge: PLX Technology, Inc. PEX 8605 PCI Express 4-port Gen2 Switch (rev aa)
02:03.0 PCI bridge: PLX Technology, Inc. PEX 8605 PCI Express 4-port Gen2 Switch (rev aa)
04:00.0 Network controller: Qualcomm Atheros AR93xx Wireless Network Adapter (rev 01)

When I tried to connect WiFi with connman, it said “cfg80211: DFS Master region: unset” and failed to connect. Could it affect WiFi connectivity ?

connmanctl> agent on
Agent registered
connmanctl> connect wifi_207c8f56bcde_48414d455f41355f36326661_managed_psk
Agent RequestInput wifi_207c8f56bcde_48414d455f41355f36326661_managed_psk
  Passphrase = [ Type=psk, Requirement=mandatory ]
Passphrase? 1234567
connmanctl> [   94.781715] wlp4s0: authenticate with 9c:41:7c:36:2f:a8
[   94.798098] wlp4s0: send auth to 9c:41:7c:36:2f:a8 (try 1/3)
[   96.023843] wlp4s0: send auth to 9c:41:7c:36:2f:a8 (try 2/3)
[   96.798590] wlp4s0: authenticated
[   96.802616] ath9k 0000:04:00.0 wlp4s0: disabling HT/VHT due to WEP/TKIP use
[   96.813919] wlp4s0: associate with 9c:41:7c:36:2f:a8 (try 1/3)
[   98.053835] wlp4s0: associate with 9c:41:7c:36:2f:a8 (try 2/3)
[   98.809213] wlp4s0: RX AssocResp from 9c:41:7c:36:2f:a8 (capab=0x431 status=0 aid=1)
[   98.817331] wlp4s0: associated
[   98.820503] IPv6: ADDRCONF(NETDEV_CHANGE): wlp4s0: link becomes ready
[  103.584269] cfg80211: Calling CRDA to update world regulatory domain
[  103.625214] cfg80211: World regulatory domain updated:
[  103.630383] cfg80211:  DFS Master region: unset
[  103.634835] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[  103.643228] cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 2000 mBm)
[  103.650700] cfg80211:   (2457000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm)
[  103.658128] cfg80211:   (2474000 KHz - 2494000 KHz @ 20000 KHz), (N/A, 2000 mBm)
[  103.665557] cfg80211:   (5170000 KHz - 5250000 KHz @ 80000 KHz), (N/A, 2000 mBm)
[  103.672959] cfg80211:   (5250000 KHz - 5330000 KHz @ 80000 KHz), (N/A, 2000 mBm)
[  103.680373] cfg80211:   (5490000 KHz - 5730000 KHz @ 160000 KHz), (N/A, 2000 mBm)
[  103.688207] cfg80211:   (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 2000 mBm)
[  103.698456] cfg80211:   (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 0 mBm)
[  103.710523] IPv6: ADDRCONF(NETDEV_UP): wlp4s0: link is not ready
Error /net/connman/service/wifi_207c8f56bcde_48414d455f41355f36326661_managed_psk: Operation aborted
connmanctl>

You may have to set the regulatory domain e.g. as follows by replacing IN with your resp. country:

iw reg set IN

For more information please have a look at the following website.