# Wireless radio has been killed for interface wlan0...

## meulie

Hi all!

My wifi-interface (iwl4965agn chipset) has the following problem.

```
/etc/init.d/net.wlan0 stop
```

 works fine, but when I then do a 

```
/etc/init.d/net.wlan0 start
```

 I get: 

```
Wireless radio has been killed for interface wlan0
```

Why? How do I fix this?

----------

## alien

Is it a notebook? If yes, do you have an on/off switch for your WLAN?

Best wishes

----------

## meulie

 *alien wrote:*   

> Is it a notebook? If yes, do you have an on/off switch for your WLAN?
> 
> Best wishes

 

Yes, and yes...

But I have not touched that switch. It's on the 'on' position.

----------

## drescherjm

I have seen this a few times for the new iwlwifi driver built in the 2.6.24 kernel. When it happens the only way I have found to fix it is reboot.

----------

## MostAwesomeDude

I know it's probably not what you want, but unloading the module and then reloading the module works. Also using NetworkManager or any other utility that knows about RF killswitches will work.

----------

## drescherjm

I believe I tried that on Sunday (which was the last failure). I will remember to do that the next time and post back. For me this seems to be triggered (probably 1 out of 10 times) by having the laptop suspend to ram.

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## meulie

 *MostAwesomeDude wrote:*   

> I know it's probably not what you want, but unloading the module and then reloading the module works.

 

Hmm, does not work on mine... I even tried: remove module -> put wifi-switch to wireless-off -> put wifi-switch to wireless-on -> load module.

I still get 

```
Wireless radio has been killed for interface wlan0
```

  :Crying or Very sad: 

----------

## b0clem

i have the same problem with you, my wireless radio is iwl3945, and i try to unload the module (modprobe -r iw3945) and load it again(modprobe iwl3945), it's work for me, just try it.

 :Very Happy: 

----------

## meulie

 *b0clem wrote:*   

> it's work for me, just try it.
> 
> 

 

I did try that... It does not help...    :Confused: 

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## drescherjm

 *Quote:*   

> 
> 
> I did try that... It does not help...   

 

It did not work for me either but it may be because of dhcpcd and the init scripts. Because after the second time I did reloaded the driver the error message went away but then I could not start net.wlan1 (becuase it said it was already starting) and after killing dhcpcd and zaping the init script it still did not work. then just tyring to get dhcpcd to give me an ipaddress that did not work either. However when starting wlan1 it did say it found the correct access point just I could not get an ipaddress. I will have to debug that further[/quote] next time it happens to me.

----------

## alien

Problem solved?

If not, would you check your kernel konfig 

```
Networking  --->

              [*] Networking support

                         <*>   RF switch subsystem support  --->

                                 --- RF switch subsystem support

                                 <*>   Input layer to RF switch connector

```

I hope it will help.

Best wishes!

----------

## drescherjm

I have  RF switch subsystem support disabled.

----------

## drescherjm

Enabling the RF switch connector did not help.

----------

## termite

I have a little 'restartwireless' script.  It solves this problem most of the time, but I occasionally have to reboot: 

```
#!/bin/sh

echo "Removing iwl3945"

rmmod iwl3945

echo "Removing mac80211"

rmmod mac80211

echo "Adding mac80211"

modprobe mac80211

echo "Adding iwl3945"

modprobe iwl3945

sleep 1

/etc/init.d/net.eth1 restart
```

The sleep 1 makes it wait 1 second, which appears to help.  You may want to try to increase that to 2 or 3 if you're still having trouble.  Obviously, change eth1 to whatever your adapter name is.  I'm assuming you're using iwl3945 and have mac80211 compiled as a module.  If not, try to change the kernel config to be so.

----------

## Hamlet

My way to make it work again on an Fujitsu-Siemens Amilo 1520:

1. stop the service

2. unload the driver

3. reload the driver

4. push the wireless activation button on my laptop

5. start the service again.

In fact, seems that Linux is able to switch the radio antenna off when I stop the service, but not to turn it on again afterwards.

Note that until I press the button `iwconfig` does not show me the 'wlan0' interface.

```
/etc/init.d/net.wlan0 stop

rmmod iwl3945

modprobe iwl3945

# push the button

/etc/init.d/net.wlan0 start

```

I must check if some kind of bug has been reported to the developers about this. I've not clear which is the operation which kills the radio antenna.

----------

## bszente

Hello meulie,

 *meulie wrote:*   

> 
> 
> ```
> Wireless radio has been killed for interface wlan0
> ```
> ...

 

Do you have NetworkManager installed? If yes, it might be related to NetworkManager. Please try the following:

 - restart your computer;

 - login as root in console;

 - stop the wlan0 interface if it is the case:

```
# /etc/init.d/net.wlan0 stop
```

 - disable NetworkManager daemon:

```
# /etc/init.d/NetworkManager stop

# /etc/init.d/NetworkManagerDispatcher stop
```

 - start now the wlan0 interface:

```
# /etc/init.d/net.wlan0 start
```

Will it start now? On my laptop I found that NetworkManager might disable the radio. I don't know why.

----------

## ericxx2005

I've had success with adding:

 *Quote:*   

> 
> 
> iwconfig txpower on
> 
> iwconfig txpower ## <--Put your wireless power in dBm here

 

in /etc/conf.d/local.start[glep=][/glep]

----------

## jesnow

Note: I have checked that the hardware workes by booting Vista, which despite all its problems "just works" on this hardware, whereas iwl3945 does not. 

 *ericxx2005 wrote:*   

> I've had success with adding:
> 
>  *Quote:*   
> 
> iwconfig txpower on
> ...

 

This didn't work for me, nor did *any* of the solutions on this page. 

It does seem to be related to the hardware being deactivated and not reactivated somehow.

Jon.

----------

## EmherYok

 *jesnow wrote:*   

> Note: I have checked that the hardware workes by booting Vista, which despite all its problems "just works" on this hardware, whereas iwl3945 does not. 
> 
>  *ericxx2005 wrote:*   I've had success with adding:
> 
>  *Quote:*   
> ...

 

Well ... unfortunately wireless rarely "just works" under Linux.  But trust me, it's 100x better than it used to be!

However, the above actually SOVED the problem for me!  It's a hack and not a permanent solution, however.  Oh, and there seems to be a typo above.

To see if this solution will work at all, run the following commands as root (instead of in local.start):

```

iwconfig wlan0 txpower on

iwconfig wlan0 txpower 30 #Or whatever

/etc/init.d/net.wlan0 restart

```

Like I said, this is just a hack until someone finds out what's really causing the issue -- I'll keep digging.

----------

## jesnow

 *EmherYok wrote:*   

>  *jesnow wrote:*   Note: I have checked that the hardware workes by booting Vista, which despite all its problems "just works" on this hardware, whereas iwl3945 does not. 
> 
>  *ericxx2005 wrote:*   I've had success with adding:
> 
>  *Quote:*   
> ...

 

didn't woork for me. 

Jon.

----------

## meulie

 *ericxx2005 wrote:*   

> I've had success with adding:
> 
>  *Quote:*   
> 
> iwconfig txpower on
> ...

 

I don't have the faintest idea why, but this works for me as well!  :Smile: 

Does it make any difference what I set the ## to? If yes, what is the optimal value?   :Cool: 

----------

## ericxx2005

 *Quote:*   

> Does it make any difference what I set the ## to? If yes, what is the optimal value? 

 

It should be based on what your wireless card's transmit power is.  From 

```
man iwconfig
```

 *Quote:*   

> 
> 
>        txpower
> 
>               For cards supporting multiple transmit powers, sets the transmit
> ...

 

----------

## meulie

 *ericxx2005 wrote:*   

>  *Quote:*   Does it make any difference what I set the ## to? If yes, what is the optimal value?  
> 
> It should be based on what your wireless card's transmit power is.

 

The logical next question: Is there an easy way to determine this value, other than RTFM?    :Cool: 

----------

## AwoL

Yeah, nothing here seems to have worked for me.  The weird thing is, it seems like it works on and off when I was changing some things in my kernel.  For instance, when I enabled mtrr - I started getting the error.  If I disabled it and rebooted, it was fine.  However, I added some features and now the radio is refusing to turn back on.  I wish I knew the connection.

----------

## DirtyHairy

Among the sysfs files belonging to the driver (somewhere in /sys/bus/pci/drivers/iwl3945) there is a file rf_kill. At least with ipw3945, this could be used to manually power up and down the radio, and it seems to work with iwlwifi, too (I just checked).

----------

## AwoL

It looks like I have that file in /sys/bus/pci/drivers/iwl4965/0000:03:00.0/ - but the value changes back to 1 when I try to restart the wlan0 interface.  So, it rekills.

----------

## DirtyHairy

Can you reenable it via 

```
echo 0 > /sys/bus/pci/drivers/iwl4965/0000:03:00.0/rf_kill
```

?

----------

## AwoL

Yes I can, and the value is accepted.  However, when I restart the network interface, the value is changed back to 1.

----------

## AwoL

I was able to get it to work after a reboot if I did "echo 0 > /sys/bus/pci/drivers/iwl4965/*/rf_kill".  However, when I rebooted again it was still broken.  Google apparently said that some people believed this was a BIOS problem, and that resetting the BIOS to default values seemed to fix it for them.  So far, this is working for me too.

----------

## DirtyHairy

If the problem resurfaces, you can add the hack to the preup part of the network configuration  :Smile: 

----------

## Pearlseattle

For me it works as follows:

```

/etc/init.d/net.wlan0 start

sleep 5

iwconfig wlan0 txpower on

sleep 5

/etc/init.d/net.wlan0 start

```

I had just before the sleep set to 2, and it didn't work.

----------

## farmer-Bri

Thanks everyone, I got the 3945abg in my Sony TZ17 working with the following:

```

echo 0 > /sys/bus/pci/drivers/iwl3945/*/rf_kill

iwconfig wlan0 txpower on

/etc/init.d/net.wlan0 start

```

I'm assuming that just turning txpower on without setting a value uses a default so this may be sub-optimal, but a win is a win.

----------

## cazort

Hello!  I'm having this problem too: can't restart wireless and need to restart computer to restart wireless + wireless often doesn't connect when I start the computer.  Using .24-gentoo-r8 kernel

When I run:

```
iwconfig wlan0 txpower on
```

...the screen on my laptop fades to white and I am unable to use the laptop (a Dell XPS M1130, 3945ABG wireless, Intel Mobile Integrated Graphics). It isn't a crash though...it's only something with the video, since I can change to a terminal, manually log on as root, and reboot the computer. Is there some reason that suggested command is possibly dangerous? Why should it affect other hardware like my video card? This is scary to me...if it affects the video, who knows what other damage it could do? This seems like a serious bug in something but I'm not quite sure how to report it.

----------

