Intel Dual Band Wireless-AC 7260 issues in Ubuntu 18.04

Question

I have a laptop with with the Intel Dual Band Wireless-AC 7260 and am running Ubuntu 18.04 (although the problem existed with 17.10 and I presume this is a general problem). At home the Wifi works well, however, on some networks it will intermittently disconnect. Using Gnome network manager and turning the Wi-fi off and back on could fix the issue, but not always. This could happen numerous times a day.

Answer 1

After much research and reading the Kernel documentation on this, I found that making all the following changes work.

Change the wi-fi country code (thanks to this post). As root edit /etc/default/crda and set the following to your country code:

REGDOMAIN={ISO COUNTRY CODE}

Disable Bluetooth, although this is a dual-band adapter, it's not good at handling Bluetooth and wi-fi at the same time. From the Kernel documentation:

For users of these devices who have problems when Wi-Fi and Bluetooth are running concurrently, we suggest to disable BT Coex by loading iwlwifi with bt_coex_active=0 as a module parameter.

Also from the Kernel documentation also discusses that the device does not handle 2.4 Ghz noise very well and recommends the following:

- Disable Wi-Fi's power save (prevent the PCIe link to go to power save): power_save=0 module parameter for iwlmvm
- Disable USB3 in BIOS (if possible), it not, just stop using it
- Disable 40MHz on 2.4GHz: cfg80211_disable_40mhz_24ghz module parameter
- Use 5GHz band (on devices that support 5GHz operation)

In a nutshell, I did not disable USB3 in BIOS. But did the others, to implement these changes add the following line to /etc/modprobe.d/iwlwifi.conf:

options iwlwifi bt_coex_active=0 swcrypto=1 11n_disable=8 

UPDATE: Thanks to @chili555, the Kernel driver page appears to be out-dated/incorrect, the power_scheme value does not exists and appears that we should use power_save=0. Documentation updated.

A good resource for debugging the iwlwifi driver is https://support.system76.com/articles/wireless/

Answer 2

You can fix this issue temporarily by running this code (The selected Country should support Dual-band 5Ghz US/DE/...):

 # iw reg set US

or add this as a permanent solution:

echo "COUNTRY=US" > /etc/sysconfig/regdomain

And these code as check:

 # iw reg get
 # iw list