Where should I add iwconfig options to make them permanent?

peterx14 · 02-04-2010, 04:33 AM

Hi all,

I have recently setup a computer running Ubuntu 9.10 with an Edimax EW-7128G PCI card. It works fine, except when I try to connect to this computer remotely, there's lot of packet loss.

Anyway, to cut a long story short, I have found I can solve this by disabling power management using:

Code:

$ sudo iwconfig wlan0 power off

But where is the correct place to insert this so that power management is always disabled?

FYI - This machine is configured to automatically login, and I have gone through the network manager and set the wireless connection to be "Available to all users". Without doing this, at bootup, it would ask for the user password in order to enable the WiFi!

TIA,

Peter.

neonsignal · 02-04-2010, 04:55 AM

Have a look at 'man interfaces', which covers setting up /etc/network/interfaces. For example, there are the pre-up and post-up options which allow commands to be run before/after the interface is brought up, which might be a place to place the power management settings.

Alternatively (and this might work better with network manager in control) is to modify the scripts in /etc/network/if-pre-up.d - you might already find one for wireless-tools. For example, some have the lines

Code:

if [ -n "$IF_WIRELESS_POWER" ]; then
  $IWCONFIG "$IFACE" power $IF_WIRELESS_POWER

which means it is just a matter of setting IF_WIRELESS_POWER to 'off' at the start of the script.

peterx14 · 02-04-2010, 09:23 AM

Thanks loads for your reply!

Quote:

Originally Posted by neonsignal

Alternatively (and this might work better with network manager in control) is to modify the scripts in /etc/network/if-pre-up.d - you might already find one for wireless-tools. For example, some have the lines

Code:

if [ -n "$IF_WIRELESS_POWER" ]; then
  $IWCONFIG "$IFACE" power $IF_WIRELESS_POWER

which means it is just a matter of setting IF_WIRELESS_POWER to 'off' at the start of the script.

That _should_ work, but it doesn't. As far as I can figure out, the folks working on the Gnome Network Manager decided that they didn't need to support the if-pre-up scripts! Nope, I've no idea why they thought that was a good idea... and I've also no idea why the directory still exists in Ubuntu 9.10 when it doesn't seem to get used.

Anyway, I've got it working now thanks to your pointers -- this is what I did:

Create a network "up" script:

Code:

$ sudo vim /etc/network/if-up/wifi_disable_power_management

And paste in the following:

Code:

#!/bin/sh
iwconfig "$IFACE" power off

Once the file has been saved, make it executable:

Code:

$ sudo chmod +x /etc/network/if-up/wifi_disable_power_management

I subsequently found this post which is like your suggestion, but they've then symlinked the wireless-tools file to the if-up.d directory to make it get executed!!

All working now though -- thanks again!

Kerridis · 05-21-2010, 09:48 AM

What is the difference to writing "iwconfig wlan0 power off" into /etc/rc.local?

darkcity · 05-24-2010, 04:02 PM

Does the wireless connection have to be up and running to issue 'iwconfig... ...power off' command?

I've been experimenting with puppy linux using 'iwconfig wlan0 rate 5.5M fixed' to get better connection. Someone suggested adding a 'sleep 30' line before to allow connection to be made and then configured.