Forwarding Ubuntu bug #1037718: 

I have set the wifi "options iwlegacy led_mode=1" in /etc/modprobe.d/wlan.conf to stop the led blinking, which works as expected. The problem I have found is that if I suspend the laptop then upon resuming the wifi led is permanently off yet the wifi still works properly.

Also it is not just suspend that affects the LED, disabling wifi from network menu or using the hardware wifi switch on the laptop results in the same problem that the LED is permanently off after turning wifi back on.

Just to clarify that when the led is set to blinking (default) the led works as expected so there is no issue with it being off upon resume etc.

This is regression going from kernel 2.6.38 (Natty) to 2.6.39 (Oneiric).
It is likely somewhere in the splitting of iwl3945 drivers into iwlegacy directory[1] however I am struggling to get any further narrowing it down as either I am facing kernel build errors or wireless is not working on the builds that are in the middle of the above iwlegacy commits.

WORKAROUND: To get the LED back on without rebooting reload the module:
rmmod iwl3945 && modprobe iwl3945

WORKAROUND: For the suspend issue is to add to /etc/pm/config.d/modules :
SUSPEND_MODULES="iwl3945"

[1] https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/drivers/net/wireless/iwlegacy?h=linux-2.6.39.y