Intel PRO/Wireless 3945ABG stopped working

Question

my wlan works right after i installed ubuntu 11.04, after several hours it just stop detecting my wlan. my wlan is an Intel PRO/Wireless 3945ABG [Golan} Network Connection (rev 02). i downloaded driver for linux from intel website but i don't know how to install it. PLEASE HELP!

Solution 1

I have the same network hardware in my laptop. It works just fine with the standard driver that came with Ubuntu. When it stops seeing wireless networks, that usually means I've accidentally toggled the wifi kill switch on the front of my laptop.

I've had occasional problems, through, with earlier versions of Ubuntu. Sometimes those problems were resolved by unloading and reloading the driver module:

sudo modprobe -r iwl3945
sudo modprobe iwl3945

although I should mention that at one point the unload command used to cause the entire system to freeze. Caveat emptor.

Solution 2

I realise the OP to this question was last seen in July, so my answer is more generic. To resolve problems like this will probably need some interaction to try out stuff.

• Suggestion 1:

Why do you need to install a new driver? Sometimes the version in the kernel is buggy. Fortunately, the kernel team do release a backport of new & updated drivers & their firmware a few months after each Ubuntu release. For natty, you can install this by:

sudo apt-get install linux-backports-modules-cw-2.6.39-generic

Then reboot.

• Suggestion 2:

Check if the wireless card is actually blocked. Running rfkill list is very useful - if the wireless is actually recognised there can be two types of blocking being reported - a soft block and a hard block.

A hard-block is likely to be a hardware switch - a physical hardware switch/ a Fn key switch or maybe a BIOS option.

A soft-block can sometimes be resolved by running:

sudo rfkill unblock wifi; sudo rfkill unblock all

Followed by either:

ifconfig wlan0

to start the wireless lan OR select "enable wireless" on Network Manager.

• Suggestion 3:

Removing and readding the kernel module can sometimes activate the wireless card. It is also very useful to diagnose what the Kernel errors are:

sudo modprobe -r iwl3945
sudo modprobe iwl3945
dmesg | tail -n 50

Have a close look at the output - sometimes a firmware update can resolve this - see the linked question below.

• Suggestion 4:

Running the modprobe options above should write out a iwl3945.conf file in \etc\modprobe.d\. The dmesg message could indicate that an alernative value(s) are required e.g.

alias wlan0 iwl3945
options iwl3945 disable_hw_scan=1

_source

---

Linked Question:

1. "SIOCSIFFLAGS: Operation not possible due to RF-kill"?

Comments

[Ross Fleming]

Does this card not work on 12.04? My laptop has the 4965AGN which didn't work until 12.04.

[Admin]

My wlan0 stays down and I cannot see any network with this tip, using IBM x60s laptop with the same hw. Just upgraded to Ubuntu 11.04.

[Admin]

Got it fixed! I probably had two problems at the same time, this issue and the hard block switch issue. Anyway got things working again with this instructions here and turning on the small switch, never even noticed that thing under dirt.

[Pierre]

does it matter if my machine has now realtek wireless driver and intel Golan driver, it works but how long? I apparently installed realtek driver besides the intel driver.

[nilsonneto]

I presume you have downloaded and installed these manually? No - generally. The kernel is the key here - it will look for the most appropriate driver according to the device. In the rarest of circumstances, you can get a clashing kernel module - that is when you have to "black-list" a kernel module. I dont see any reason why a realtek and golan driver would clash with a 3945 wireless card. The 3945 is a "maintained" kernel module - it should be supported from now and into the future with new ubuntu and kernel versions automatically.