Unstable wireless with Intel 7260 + iwlwifi after upgrade to 15.04

I have similar problems with my Intel 7260 wifi and did some research on how to fix these issues.

It turns out that lots of people have problems with this wifi card and its related driver the iwlwifi. However, it seems there is no easy apply and forget fix as people are reporting different problems (also due to different APs being used of course). Hence, some testing is has to be done.

The following links should be helpful:

I found several related bug reports on launchpad, see here, here, here, and here.

Furthermore, on the Archwiki there is a useful troubleshooting section for the iwlwifi driver.

Last but not least here is also a brief summary on how to fix iwlwifi related problems.

Some suggested solutions are:

• Turn off bluetooth (use rfkill or turn off in Bios)
• Turn OFF 802.11n mode (in /etc/modprobe.d/iwlwifi.conf add options iwlwifi 11n_disable=1)
• Turn ON link aggregation (in /etc/modprobe.d/iwlwifi.conf add options iwlwifi 11n_disable=8)
• Turn OFF watchdog (in /etc/modprobe.d/iwlwifi.conf add options iwlwifi wd_disable=1)
• Turn off power saving features ($ sudo iw wlan0 set power_save off)
• Set regulatory domain ($ sudo iw reg set <country code>)

In my case the stability problems were coming from frequent disconnects showing up in the syslog (-> dmesg) as follows:

wlan0: deauthenticating from ....... by local choice (Reason: 3=DEAUTH_LEAVING)

I am running Ubuntu 15.04 (x64) with a 3.19 Linux kernel.

In my case it seems that the problems are fixed just by turning on link aggregation (11n_disable=8). Turning off power saving also seems to help. This holds for the 2.4GHz network.

For the 5GHz network I could not solve the problems and the link is highly unstable.

For how to turn off wifi power management permanently see here and here.

Before you go messing with your kernel as lpbug suggested, I think you should try tinkering with other things that don't have such a high risk of breaking things.

The fact that your device seems to be loading data slowly leads me to believe that the problem might be an issue between your router and your computer. Have you tested the data rate in another network while comparing to another device as a benchmark (your phone)? That might help us narrow down what is wrong.

Have you tried turning off 802.11n in your /etc/modprobe.d/iwlwifi.conf? I have the same wireless card and turning this off greatly improved my network's performance.

To turn it off, add the following line to /etc/modprobe.d/iwlwifi.conf:

options iwlwifi 11n_disable=1

Now restart the module:

sudo modprobe -r iwlmvm
sudo modprobe -r iwlwifi
sudo modprobe iwlwifi

Note for other readers with a similar problem to OP: you might have to replace iwlmvm above with iwldvm, depending on your system.

Let me know if that helps at all.

By the way, to address your second question from your edit, yes, the iwlwifi config file should have the exact lines you listed.

First of all, I should preface this with the fact that my network card is the Dual band version of the Intel Wireless N 7260 REV=0x144. but according to the 3rd post of this thread, it seems like out hardware is the same. I've had this unstable wifi problem for close to a year now and it seems like other with this card have had the same issue. This persisted until I recently tried different kernels.

The symptom for the unstable wifi would include (in order of most common occurence): Not being able to connect to wifi network upon returning from suspsend unless the computer has been restarted, or iwlwifi restarted; taking a really, really long time to connect to a network (on the order of a minute); being disconnected randomly from the wifi network I am on.

I dual boot windows 7 with this and the same piece of hardware performs very well. This lead me to believe that this is more of a software problem. I tried out the 3.17.0 rc2 mainline kernel and my unstable wifi problem disappeared, now it only takes me about 10 seconds to connect to a wifi network and connections are rock solid. To my knowledge, the 3.17 kernels use firmware:iwlwifi-7260-9.ucode so if you can just try that version of iwlwifi it may work better.

HOWEVER...

You should read this post before considering to do the same thing as I had. Before, I was getting 120 mbps up and down easily when I had a good wifi connection. Now, I only get 20 mbps up and down (tested this in windows 7 as control, and it seems like it is also getting 120+ mbps as before). I am unsure if this is a result of the kernel switch. In my case, it is a tradeoff between speed and stability and I would take 20 mbps of stable wifi over 120 mbps of unstable wifi.

If you decide to proceed: the steps I took for installing the new kernel:

cd /tmp

then

wget the following from the 3.17.0 rc2 mainline page:

linux-headers-3.17.0-031700rc2-lowlatency_3.17.0-031700rc2.201408251935_amd64.deb

linux-headers-3.17.0-031700rc2_3.17.0-031700rc2.201408251935_all.deb

linux-image-3.17.0-031700rc2-lowlatency_3.17.0-031700rc2.201408251935_amd64.deb

finally, sudo dpkg -i linux-headers-3.17.0-*.deb linux-image-3.17.0-*.deb

then reboot and check that the firmware loaded is version 9.

I really hope this works for you.