every once and a while… laptops and notebooks run out of battery… and when one manages to plug them in just 1% before stalling… the wifi on Debian might already be in hibernation and hardware on off does not help to bring it back to life.

(this ought to happen automatically when power cord is plugged in but it’s not in:

root@debian:~# hostnamectl 
   Static hostname: debian
         Icon name: computer-laptop
           Chassis: laptop
  Operating System: Debian GNU/Linux 9 (stretch)
            Kernel: Linux 4.9.0-11-amd64
      Architecture: x86-64

# how to fix it, restart network manager
systemctl restart NetworkManager.service

# might show something like:
[ 2913.745644] wlp3s0: deauthenticating from 98:..:..:..:.. by local choice (Reason: 3=DEAUTH_LEAVING)
[ 2913.829419] PM: Hibernation mode set to 'suspend'
[ 2913.860431] (NULL device *): firmware: direct-loading firmware iwlwifi-7260-17.ucode
[ 2913.860448] PM: Syncing filesystems ... 
[ 3362.080393] thinkpad_acpi: EC reports that Thermal Table has changed