Flickering Wireless LED in Ubuntu 8.10

A quick solution to that darned flashing wireless light in Ubuntu 8.10 – works on my Dell Vostro anyway.

This solution didn’t work for me – I had to make a slight adjustment to the directories updated. It does give some background on how it works if you’re interested though.
Save the following file as “/etc/network/if-up.d/iwl-no-blink” and make it executable for all.

if [ "$IFACE" = "wlan0" ]; then
  for dir in /sys/class/leds/iwl-phy*; do
    echo none > $dir/trigger

Now the wireless light is off when disconnected, blinks when I’m connecting, and is steady on when I’m connected.

Updated, 23th March 09
…but it doesn’t work on resume from suspend. When my Vostro 1310 resumes from suspend, it’s back to the defaults. I fixed this behaviour by adding a script /etc/pm/sleep.d/00wireless, executable for all.

case "$1" in

Updated, thanks Richard
The easy way to make the script executable for all; you might be prompted for your password.

sudo chmod u+x /etc/network/if-up.d/iwl-no-blink

Meaning: Modify the file permissions on /etc/network/if-up.d/iwl-no-blink to add permission to execute for all users.
Then you can check the permissions with:

you@your-computer:~$ ls -lart /etc/network/if-up.d/iwl-no-blink
-rwxr-xr-x 1 root root 119 2008-11-02 11:36 /etc/network/if-up.d/iwl-no-blink

The -rwxr-xr-x means that any user can execute the script.


Author: brabster

Software developer in the North of England

16 thoughts on “Flickering Wireless LED in Ubuntu 8.10”

  1. I have same problem on my Dell Inspiron 6400 but how do you make it “executable for all”? I have generated a file as required but the LED still blinks!

  2. Thank you very much for your help Paul, this works on my HP G3050EA!! Cheers from Nice, France πŸ™‚

  3. THANK YOU!!!
    Men you are GOD!

    Vitej como decimo aqui en la mierda grande TE QUIERO EN PUTA!

    Working in a HP 1020us… with 9.04

  4. Hi Alan

    You make the file ‘executable for all’ with the command

    sudo chmod u+x /etc/network/if-up.d/iwl-no-blink

    There’s some more detail in the post, it starts ‘Updated, thanks Richard’. I should probably have dropped a reply directly to Richard’s comment to make it clearer, will do in future.


  5. But it doesn’t work om my Vostro A860 😦
    Instead of led it switch on/off indicator of Bluetooth in system tray, but wifi led isn’t work

  6. @virgus
    That sounds weird… I’m not sure what to suggest as troubleshooting, I sure don’t have an A680 to have a look at I’m afraid. So here’s what I looked at to get the script working as it is on my machine. Perhaps there are differences with your machine.

    I would have a look round in the /sys/class/leds directory. My knowledge here is based largely on poking, trial and error, but my understanding is:

    paul@paul-laptop:~$ ls /sys/class/leds
    iwl-phy0:assoc iwl-phy0:radio iwl-phy0:RX iwl-phy0:TX
    There are 4 behaviours for the wireless LED defined here, RX and TX being receive and transmit.

    Looking in, say, the iwl-phy0:TX directory, there’s a ‘trigger’ file. Looking inside:

    paul@paul-laptop:~$ cat /sys/class/leds/iwl-phy0:TX/trigger
    none ACAD-online BAT1-charging-or-full BAT1-charging BAT1-full mmc0 phy0rx [phy0tx] phy0assoc phy0radio rfkill0

    The square brackets around phy0tx means that the LED will flash when transmitting. When I echo ‘none’ into there, as in my script above:

    paul@paul-laptop:~$ cat /sys/class/leds/iwl-phy0:TX/trigger
    [none] ACAD-online BAT1-charging-or-full BAT1-charging BAT1-full mmc0 phy0rx phy0tx phy0assoc phy0radio rfkill0

    Which means that the LED doesn’t react to any states at all. Hope that’s helpful.

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