Comment 38 for bug 1442411

Mostly just confirming what @boratko already shared, plus perhaps a few new details:

The ingredients needed to reproduce this bug on Vivid:

1) Intel 3160 WiFi card

2) Boot with bluetooth enabled (turn on in the bluetooth indicator and reboot if needed)

3) Connect to a 2.4 GHz N router

In this situation, I've not once successfully connected to my AP. When my SSID shows up in NetworkManager, attempting to connect my AP will fail and there is an error in dmesg about the authentication timing out. But occasionally the SSID wont even show up in NetworkManager, so I can't try to connect to it.

With the same hardware and same scenario, this bug is not present when running 14.04.2 (with Utopic HWE).

Some other details:

1) Turning off bluetooth (from the indicator) and rebooting seems a reliable way to work-around this

2) There are no issues when connecting to a 5 GHz AC router, and based on feedback from System76 customers, it seems 5 GHz N is fine and 2.4 GHz G is likewise fine ( the problem is seemingly limited to just 2.4 GHz N)

3) This problem is not present with Intel 7260 WiFi cards, only the 3160

4) I confirmed that the 4.1rc2 mainline build fixes this issue:

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.1-rc2-vivid/