For a long time I was happy with my Debian install, everything was working fine and as expected… that is until, recent, update.
After normal kernel update (to another iteration of 3.16 version), something around mid January / February 2017, I did noticed that after reboot my laptop don’t bring up WLAN adapter up and states, in GNOME menu under Wi-Fi, that device is “Hardware disabled”.
Issuing command like:
ifconfig wlan0 up
resulted in:
SIOCSIFFLAGS: Operation not possible due to RF-kill
Issuing rfkill to list shows that:
rfkill list all
1: phy0: Wireless LAN
Soft blocked: no
Hard blocked: yes
indeed device is hard locked. Hard lock occur when i.e. user hit, specific to manufacturer, lock button to lock WLAN device. In my case I do use Dell XPS 15 9530 with do comes with:
06:00.0 Network controller: Intel Corporation Wireless 7260 (rev 6b)
Subsystem: Intel Corporation Dual Band Wireless-AC 7260
Kernel driver in use: iwlwifi
that implements both WiFi and Bluetooth device and is handled by iwlwifi module.
Hard lock is located as media button “under” “Print Screen” that, depending on BIOS settings, can be accessed directly or via combination of keys FN+PrintScreen. Pressing that does nothing. I’m not sure when this stopped to work as I don’t block my WiFi but definitely something was not handled properly because i.e. issuing:
showkey --scancodes
didn’t catch any keys (see below for more info).
Using:
rfkill unblock all
didn’t solved the problem either.
What I did notice is that when waking up from sleep it did bring up WLAN and WiFi was operating correctly (as Bluetooth). To do so I was using FN+Insert key combination (again specific to my Dell XPS 15 9530).
SOLUTION:
What I did tried next, and that solved issue for me, as last resort was updating kernel using backports.
To do so I added (as root) to:
/etc/apt/sources.list
fallowing entries:
deb http://ftp.[lang].debian.org/debian/ jessie-backports contrib main non-free
Replace [lang] with appropriate language or switch to HTTP.
After that issuing fallowing command:
apt-get update
apt-get -t jessie-backports install linux-image-amd64
apt-get -t jessie-backports install firmware-iwlwifi
will install latest kernel, as of writing this it was 4.9.0, and iwlwifi firmware.
Rebooting and from now on WLAN did correctly started.
Hardware WLAN block key started to work correctly.
NOTE about showkey –scancodes, after update showkey also didn’t catch WLAN disable button.