How I stopped my ubuntu from waking up from suspend

My Ubuntu 19.04 Laptop had the annoying property to wake up about 1 sec after being suspended (e.g the lid was closed). It took me some wasted battery charges to fix this problem. So for everyone who has similar problems (and for future me) here is how I fixed it.

Open /proc/acpi/wakeup in your favorite editor.

sudo vim /proc/acpi/wakeup

Which looked like this:

Device	S-state	  Status   Sysfs node
LANC	  S5	*enabled   pci:0000:00:19.0
EHC1	  S3	*enabled  pci:0000:00:1d.0
EHC2	  S3	*enabled  pci:0000:00:1a.0
XHC	  S3	*enabled  pci:0000:00:14.0
PCIB	  S5	*disabled
RP02	  S4	*disabled
ECF0	  S4	*disabled
RP03	  S4	*enabled   pci:0000:00:1c.2
RP06	  S5	*disabled
NIC	  S5	*disabled
RP07	  S4	*disabled
RP08	  S4	*disabled
HST1	  S5	*disabled

Chaging EHC1, EHC2 and XHC to *disabled fixed the problem, but only until the next reboot, since /proc/acpi/wakeup is not persistent across reboots. The solution is putting a little script in /etc/rc.local (taken from here)

#!/bin/sh -e

for device in XHC EHC1 EHC2; do
    grep $device /proc/acpi/wakeup | grep enabled > /dev/null && {
        echo Disabling wakeup on $device 
        echo $device > /proc/acpi/wakeup
    }
done

exit 0

You may need to enable rc.local first.

sudo chmod +x /etc/rc.local
sudo systemctl enable rc-local

Hope it helped :)