Hacking by Walkingice: 2010/10


Ubuntu wifi connection randomly disconnect

I am using Ubuntu Linux 10.04 but had this annoying problem since Ubuntu 9.04. When I am at some place and use particular Access Point, the Wifi connection on my laptop randomly disconnect. Although I reboot laptop, reconnect to wifi, it still disconnect in less than one minute.

Image that, you open browser and enter gmail, click first unread mail then you lose connection. That repeat 100 times in one hour. Gosh !

Jserv told me the Wifi driver mode N is not so stable as my imagination. Follow his suggestion I turned off the N mode and it does not annoy me anymore. (at least now)

Here is the workaround
# unload iwlagn
$ sudo rmmod iwlagn
# load again with disable options
$ sudo modprobe iwlagn 11n_disable50=1 11n_disable=1

If it works, you can add it to /etc/modprobe.d. Once system modprobe this module, these options will be used.
$ echo "options iwlagn 11n_disable50=1 11n_disable=1" > /etc/modprobe.d/iwlagn.conf

There is another problem. If I suspend my laptop and put it into my backpack. Sometimes the hardware wifi switch will be turned off. If I resume the laptop while the wifi switch turned off, I can not turn it on anymore.

You can try this command, it works for me.
$ sudo rfkill block all
$ sudo rfkill unblock all