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testcore

Member

Registered: 2012-07-07

Posts: 8

Trying to use wireless N with iwlwifi & network manager

Have all the h/w necessary to use wireless N:

• Intel Centrino-N 1030

• Linksys E3200 running Tomato 1.28

• Linksys E4200 running dd-wrt 21286

Also updated everything today (pacman -Syu):

>uname -a
Linux hostname 3.12.9-2-ARCH #1 SMP PREEMPT Fri Jan 31 10:22:54 CET 2014 x86_64 GNU/Linux

So, with either router set up with as an AP at 2.4GHz and N-Only (the centrino 1030 doesn't support 5GHz), and the module defaults loaded, I see odd behavior.  First, once connected to either AP, Network Manager still reports the connection to be at B/G.

I checked the module config, and this part is relevant:

>modinfo iwlwifi | grep 11n
parm:           11n_disable:disable 11n functionality, bitmap: 1: full, 2: agg TX, 4: agg RX (uint)

There's a lot of chatter on the forums about earlier kernels not supporting N w/ iwlwifi, and recommending to disable it with '11n_disable=1' in /etc/modprobe.d/iwlwifi.conf.  So I tried explicitly enabling it, and assuming it's a binary value:

>cat /etc/modprobe.d/iwlwifi.conf
options iwlwifi 11n_disable=0

After reloading the module(s) (and restarting wpa_supplicant & networkmanager), the thing I'm finding confusing is that I can see evidence of this change take effect:

>cat /sys/module/iwlwifi/parameters/11n_disable
0

...but it doesn't affect the output of modinfo (same as above), nor am I able to connect to either router at N (NM still reports B/G).  Also confused how it connects at all when the routers are set to N-Only?

Rexilion

Member

Registered: 2013-12-23

Posts: 784

Re: Trying to use wireless N with iwlwifi & network manager

modinfo iwlwifi

That is not supposed to change. It just shows you the parameters and their valid configurations.

options iwlwifi 11n_disable=0
>cat /sys/module/iwlwifi/parameters/11n_disable
0

Did you check that it was not already 0?

...but it doesn't affect the output of modinfo (same as above), nor am I able to connect to either router at N (NM still reports B/G).  Also confused how it connects at all when the routers are set to N-Only?

If the card connects with the routers set to n only, then the card is capable of working with n. I usually check with nm-tools and look at the speed indicated.

Here is the thing: Routers and cards sometimes negotiate a lower speed to prevent intereference with other devices. I usually 'get' N-speed only once I start to saturate the link.

---

fs/super.c : "Self-destruct in 5 seconds.  Have a nice day...\n",

testcore

Member

Registered: 2012-07-07

Posts: 8

Re: Trying to use wireless N with iwlwifi & network manager

Hey, thanks for the response.  This is exactly the sort of clarification I was looking for, especially WRT the data returned by modinfo.

Much appreciated!