hostapd, ath5k, nl80211 - how to get it working?

Question

I have this network adapter in an Asus notebook running Manjaro Linux (based on Arch), everything up to date (Kernel: 3.10.11):

> lspci -k | grep -A 3 -i "network"
lspci: Unable to load libkmod resources: error -12
07:00.0 Ethernet controller: Qualcomm Atheros AR242x / AR542x Wireless Network Adapter (PCI-Express) (rev 01)
    Subsystem: AzureWave AW-GE780 802.11bg Wireless Mini PCIe Card
    Kernel driver in use: ath5k

iwconfig gives:

> iwconfig
wlp7s0    IEEE 802.11bg  ESSID:off/any  
          Mode:Managed  Access Point: Not-Associated   Tx-Power=20 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:off

I have hostapd 2.0 installed. My minimal config is:

interface=wlp7s0
driver=nl80211
hw_mode=g
ssid=test
channel=6

Running it gives

> hostapd test.conf
Configuration file: test.conf
Could not set interface wlp7s0 flags (UP): Operation not permitted
nl80211 driver initialization failed.

Running with sudo:

sudo hostapd test.conf
Configuration file: test.conf
nl80211: Failed to set interface wlp7s0 into AP mode
nl80211 driver initialization failed.

What is wrong here? How do I get my notebook to work as an AP?

Answer 1

Just found the answer myself (after googling hours to find the answer in a small but very important sentence in a private blog post about Ubuntu):

Disable (means stop the daemon or kill the process) networkmanager (or in some Distros network-manager) because it does take control over the (W)LAN Adapters, blocking it for other programs.

After doing this, hostapd can create the Access Point by initialising nl80211 correctly.