RHEL 7 + Intel 7260 AC Card

Standard

There are known issues with older kernels that cause major issues with the 7260 with regards to power management and the 5GHz spectra.  After dealing with a dying i7 IMC issue, I finally could spend time troubleshooting my issues.

For starters, ensure your router/AP isn’t crap.  I had that issue regardless of devices and their respective OS’s.  Once you are sure that there isn’t anything dead/dying or just plain flaky, there are a few things that can be done, one of which you have a potential choice as to how to deal with it.  Supposedly kernels beyond 3.16/3.17 have this rectified.  As we are pegged on EL7 to 3.10, until Red Hat backports the changes we have to deal with it ourselves.

For starters there are several lines we need to put into your /etc/modprobe.d/iwlwifi.conf

Here is how I went, and I will detail what each line means:

$ cat /etc/modprobe.d/iwlwifi.conf

options iwlmvm power_scheme=1

options iwlwifi bt_coex_active=N swcrypto=1 11n_disable=8

The power_scheme option is to set the power to full bore at all times.  The default is to 2 on most installations which is the adaptive mode.  This can cause issues with the device going to sleep at rather inopportune moments.  Although not necessarily your issue, something to keep note of.

The bt_coex_active option is for coexistence of BlueTooth and wireless.  They operate on the same frequency range and can cause issues.

The swcrypto option is for forcing the cryptography off of the card and onto your system CPU.  High workloads

The 11n_disable option is where I was referring to a choice.  Setting the disable to 1 will force the card into G only speeds.  This does indeed work on AC networks just fine, but will limit your connection to 54Mb/s speeds max.  Setting this to 8 will not cause that restriction but rather a link aggregation.  Here is the information from the module on this parameter:

$modinfo iwlwifi | grep 11n_disable
parm: 11n_disable:disable 11n functionality, bitmap: 1: full, 2: disable agg TX, 4: disable agg RX, 8 enable agg TX (uint)

Once you have made a choice as to what of these option you are going to implement, you can do the following commands (as root) to unload/load the kernel, of course taking the new parameters on reload.

$ sudo rmmod iwlmvm

$ sudo rmmod iwlwifi

$ sudo modprobe iwlwifi

Hopefully this information is as useful to you as it was me.  This fully rectified my constant disconnections while on AC networks with this card.

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