Hostapd won't change channels.

orsty9001 · 07-03-2014, 07:20 AM

I'm using slackware 14.1 as a router and AP. I need to change the channel of the wifi card because of interference. When I change the channel in hostapd.conf it just takes down the wireless network. I've tired to take the card down and change the channel using iwconfig but it gives me this error.

Error for wireless request "Set Frequency" (8B04) : SET failed on device wlan0 ; Device or resource busy.

I'm not sure how the wifi card could be busy when it's down. I've also tried stopping hostapd as well but get the same error.

How do I figure out what is using the card even if it's down or what can I do to change the channel of the card?

nini09 · 07-03-2014, 02:36 PM

Do you stop hostapd when changing channel?

orsty9001 · 07-03-2014, 04:53 PM

Iwconfig gives me the same error even if I try to change the channel while hostapd is stopped.

nini09 · 07-07-2014, 02:45 PM

What's iwconfig output? Is WiFi interface up-running?

orsty9001 · 07-07-2014, 09:40 PM

I stopped hostapd and took down the wireless adapter. I looked at the network adapters with ifconfig and wlan0 is gone.

iwconfig gives me this error.

Code:

Error for wireless request "Set Frequency" (8B04) :
    SET failed on device wlan0 ; Device or resource busy.

Same error if I leave the wireless adapter up.

nini09 · 07-08-2014, 02:14 PM

If wireless adapter is up, is there any other output of 'iwconfig wlan0' or just above error output?

orsty9001 · 07-08-2014, 02:37 PM

Here's the output of iwconfig wlan0.

Code:

wlan0     IEEE 802.11abgn  Mode:Master  Tx-Power=20 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off

nini09 · 07-09-2014, 02:30 PM

Normally, output of iwconfig wlan0 should be like following. Your output doesn't even have ESSID.
Do you configure wlan0 interface, such as ESSID?

Code:

wlan0 IEEE 802.11abg ESSID:"magdanoz"
Mode:Managed Frequency:2.442 GHz Access Point: 00:24:00:90:8F:38
Bit Rate=54 Mb/s Tx-Power=15 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off
Link Quality=70/70 Signal level=-39 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

orsty9001 · 07-09-2014, 03:31 PM

That's all configured in hostapd.conf.

nini09 · 07-10-2014, 02:38 PM

Following two links might help you to configure AP on slackware.
1)http://docs.slackware.com/howtos:net...s_access_point
The link is example hostapd.conf on slackware and tell you how to cinfigure other things.
2)http://wireless.kernel.org/en/users/...tation/hostapd
The link explain a little detail about parameter in hostapd.

orsty9001 · 07-11-2014, 12:08 PM

There isn't anything in those links that relate to my issue.

I appreciate your help anyway though.

jasonelve · 07-15-2014, 01:24 AM

Well as for myself I did ceased hostapd and took down the wi-fi adaptor. I considered the system plugs with ipconfig and wan is gone. As this is the second time it did happened for my professional website design site.