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The purpose of this page is to document the problems that I have found with the following device and environment:


[dylan@zenbook ~]$ lspci | grep -i net
02:00.0 Network controller: Intel Corporation Centrino Advanced-N 6235 (rev 24)

[dylan@zenbook ~]$ uname -a
Linux zenbook 3.12.6-1-iwlwifidebug #1 SMP PREEMPT Sun Dec 29 01:49:34 PST 2013 x86_64 GNU/Linux
[dylan@zenbook ~]$ 

[dylan@zenbook ~]$ pacman -Qs laptop-mode-tools
local/laptop-mode-tools 1.64-1
    A kernel mode that allows you to extend the battery life of your laptop

laptop-mode-tools uses 'iwconfig power' for power control, so:
[dylan@zenbook ~]$ iwconfig -v
iwconfig  Wireless-Tools version 29
          Compatible with Wireless Extension v11 to v22.

Kernel    Currently compiled with Wireless Extension v22.

wlan0     Recommend Wireless Extension v21 or later,
          Currently compiled with Wireless Extension v22.

Problem 1; Power save mode:

iwlwifi does not play nice with intel 6235 with powersaving mode
Router: buffalo wzr-hp-ag300n
Ping response and iperf with power plugged in just fine
Ping response with power unplugged is atrocious, iperf barely works
Resolution; Disable power save mode.  

Problem 2; Concurrent streams (2t2r):

iwlwifi does not play nice with concurrent streams
Router: tp-link wdr3600

A: Chip does not appear to play nicely with concurrent streams, as seen in an ping and iperf output

After getting the wireless card working fine with a single stream router (buffalo wzr-hp-ag300n) by disabling power-save mode, I decided to try to play around with it with a new router I had purchased.

I found a very similar problem occuring as with power save mode, except not as extreme.

B: After switching back to single stream router, ping still has problems

While the power-save mode can be turned on and off and the symptoms go away, this problem the symptoms appear to stick until a reboot.  I tried to modprobe -r the modules and re-load them, but that leads to Problem 3 - see below.

Problem 3; removing and adding modules:

modprobe -r and re-modprobing leads to non-working wireless