How to fix Atheros AR9287 wifi on Ubuntu 12.04
Posted by aspersieman on 2012-03-29
After a recent update on Ubuntu 12.04 I noticed something wrong with my network wifi connection. I could no longer connect to the internet using my notebook with my Atheros AR9287 wifi network adapter. Read on to discover how I resolved this issue.
Sure connecting is easy. It just has to GO ALL THE WAY INTO SPACE!
According to lspci my network adapter is:
$ lspci | grep Network 03:00.0 Network controller: Atheros Communications Inc. AR9287 Wireless Network Adapter (PCI-Express) (rev 01)
It is the network adapter I got with my Asus Aspire 4750G notebook. My wifi router is a Hauwei HG521c that I got from 3BB, my internet service provider in Thailand.
The problem was a little weird and difficult to diagnose and resolving it would certainly be a challenge with my limited knowledge of networking stuff.
When I looked at NetworkManager for some information I saw that I still had an IP address and that I am still connected to the network. I still saw some network traffic coming in and going out - although very, very little (like 1 - 2 kb/s).
We had had some intermittent issues with my ISP (3BB) before so I though it was due to an issue with them. Seeing as though both my brother and girlfriend, who share the place with me, were also having problems connecting and using the wifi I was pretty sure the problem was with 3BB (or at least the wifi router). The only difference between their issue and mine was that their network connection to the router would disconnect completely every now and then, where mine didn't (though nobody could connect to the internet).
I tried to connect using a LAN cable and this to my surpise worked fine. Network traffic for me was back to pre-problem speeds. One thing I also noticed is that while I was using the LAN cable, no one else using the network was having connection problems. So after a lot of searching on the internet and some tests I have concluded that it is my network adapter or the drivers for the adapter under Ubuntu 12.04 that is the cause of the issue.
Whenever I would connect this would crash the router but you wouldn't be able to tell that it had crashed. All the lights and stuff seemed to be flashing normally - except you couldn't connect to the internet. Whenever the router crashed, everyone's connection would also be disconnected, explaining the weird behavior I mentioned above.
One should note that my wifi connection worked perfectly when I connected to other networks/routers at work or a friend's place.
This is quite alarming behavior. How can connecting to a network crash the router? (Un)Fortunately this is an occurrence I found over a few different setups (different network adapters and routers) in my searches on Google - which ultimately lead me to the fix to resolve this issue on the AskUbuntu forums here.
So if you are having problems connecting via wifi consider trying this to resolve the issue. Execute the following commands:
sudo su echo "options ath9k nohwcrypt=1" > /etc/modprobe.d/ath9.conf
You can also, as root (or sudo) create a file named ath9.conf in the modprobe.d directory and make the contents "options ath9k nohwcrypt=1", like so:
sudo gedit /etc/modprobe.d/ath9.conf
Then paste "options ath9k nohwcrypt=1" in the text editor click save. In order to make it work you will need to reboot or run the following:
sudo ifconfig wlan0 down sudo rmmod -f ath9k sudo modprobe ath9k nohwcrypt=1 sudo ifconfig wlan0 up
I have been testing this for the past couple of days and it seems to work fine. It isn't crashing the router anymore and everyone seems to be able to connect as they did before the problem began.
I think I'll try to file a bug report, although I'm not sure where to file this. I guess I'll report it to Launchpad, the Ubuntu bug tracker.
I hope this post saves other people some trouble Happy internet-ing!
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