8086:0084 Intel Centrino Wireless N-1000 WiFi slow and disconnects sometimes (iwlwifi)

[Steven Keys]

I am running Xubuntu 11.10 64-bit on a Lenovo ThinkPad X220, and my WiFi is very slow and disconnects randomly (though disconnects are rare) on some WiFi networks. It also refuses to even connect to some networks. All of these are networks which have excellent signal strength and which many other people are successfully connected to. All of the networks I have problems with are unencrypted/public, but that may be pure chance. My home network (encrypted with WPA2, Netgear router) is 100% flawless. All or virtually all public/unencrypted WiFis I use experience this issue. The issue does not appear on other machines on the same connections. I believe there may be an issue with he iwlwifi driver that causes this. My wifi card and driver details are as follows:

03:00.0 Network controller [0280]: Intel Corporation Centrino Wireless-N 1000 [8086:0084]
 Subsystem: Intel Corporation Centrino Wireless-N 1000 BGN [8086:1315]
 Kernel driver in use: iwlwifi
---
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
DistroRelease: Ubuntu 11.10
InstallationMedia: Xubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111011)
Package: linux (not installed)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Tags: oneiric
Uname: Linux 3.2.5-tunerc6v1-generic x86_64
UnreportableReason: The running kernel is not an Ubuntu kernel
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin audio cdrom dialout dip fax floppy fuse lpadmin netdev plugdev sambashare scanner tape vboxusers video

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 939218

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Steven Keys (steevven1)]

You will notice (from apport data) that the kernel I am using is not the stock kernel, but this problem existed in exactly the same way when I was using the stock Xubuntu 11.10 64-bit kernel.

[Joseph Salisbury (jsalisbury)]

This may be a duplicate of bug 836250

Can you try the following to see if it is a valid work around for you?

Add this line to /etc/modprobe.d/intel-6200.conf:

options iwlagn 11n_disable=1

[Steven Keys (steevven1)]

I will try it for a few days and report back. Where does the number 6200 come from? Also, that file did not exist; I had to create it.

[Steven Keys (steevven1)]

Actually, after having tested it for just a little while, it's very obvious to me that it has no effect. I'm still having the issue.

[Joseph Salisbury (jsalisbury)]

Sorry, that is the wrong module for you wifi card. Can you try the following:

sudo rmmod iwlagn
sudo echo "options iwlagn 11n_disable=1" > /etc/modprobe.d/disable11n.conf
sudo modprobe iwlagn

[Steven Keys (steevven1)]

On the first command, I get "ERROR: Module iwlagn does not exist in /proc/modules." Perhaps that's because my kernel driver is iwlwifi, not iwlagn? I don't know a whole lot about this. Thanks for the help.

[Joseph Salisbury (jsalisbury)]

Yes, you are correct. For you module you can run:

sudo rmmod iwlagn
sudo modprobe iwlwifi 11n_disable=1

Then to make the change permanent:
echo "options iwlwifi 11n_disable=1" | sudo tee -a /etc/modprobe.d/iwlwifi-disable11n.conf

[Steven Keys (steevven1)]

You mistyped the first line again, but I corrected it. I will try this for a while and report back. Thanks.

[Steven Keys (steevven1)]

Unfortunately, your suggestion has no effect. My connection is still slow and very bad on public WiFi. Any other suggestions or things I can test to help solve the issue?

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.3 kernel[1] (Not a kernel in the daily directory). Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag(Only that one tag, please leave the other tags). This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text.

If this bug is fixed by the mainline kernel, please add the following tag 'kernel-fixed-upstream-KERNEL-VERSION'. For example, if kernel version 3.3-rc5 fixed the issue, the tag would be: 'kernel-fixed-upstream-v3.3-rc5'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[1] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.3-rc5-precise/

[Steven Keys (steevven1)]

I tested the kernel you linked to. The issue still exists. My WiFi on an unencrypted network is intermittently very slow.

[Steven Keys (steevven1)]

On second thought, I should be a better scientist and give it more testing. I barely tested it before, and it seems to be working better than usual now, but maybe it's my imagination. I'll report back in a day or two with definitive results after testing it at a few hotspots.

[Steven Keys (steevven1)]

I am now 100% confident that this bug still exists in the upstream kernel. What comes next? Thanks!

[Joseph Salisbury (jsalisbury)]

I believe this is a duplicate of bug 836250

[Steven Keys (steevven1)]

The following workaround has solved my issue on my ThinkPad X220 with Intel Centrino Wireless-N 1000 card using iwlwifi driver (except, of course, that I don't have N wireless capabilities now):

1) Create a file at /etc/modprobe.d/intel_11n_disable.conf containing this one line:
options iwlwifi 11n_disable=1

2) Run this command:
sudo update-initramfs -u

3) Reboot

[Steven Keys (steevven1)]

Follow-up on my own comment, #16: It seems that the problem is improved, but not actually fixed as I had said before. There is a definite improvement though. There are still plenty of networks on which I experience problems and slowness. Rebooting my machine brings back higher speeds for a while, until another reboot may be necessary, only on some netwroks. The WiFi activity light flashes constantly, even when I'm not doing anything. This bug is unreal.

[Adrián Acedo Jacquott (aceqott)]

Good. I have no problem to connect to my wifi network but to be sailing there are times when it gets really slow, I fall, but my network gets slow and takes too long to connect, I have to give several times a page.
What I can do? Help, please.

[Jaime Giraldo (sposmen)]

Hi Steven,

Your suggestion solve a similar problem on my Samsung with Intel Centrino N-130. Thanks!