Issues

Bluetooth not connecting to A2DP devices automatically in Ubuntu 18.04

The Bluez library included in 18.04 has some issues reconnecting to Bluetooth devices (independent of the Dell XPS). Fix is to includ a PPA as described in this article.

Wifi crashing/missing every other suspend/resume (Also prevents sleep) WORKAROUND

Update: apparently Dell/Canonical has implemented their own workaround for this in package oem-workaround-bt-auto-resume-lp1774582

tee /lib/systemd/system-sleep/rfkill-bluetooth-workaround <<EOF
#!/bin/sh
set -e

if [ "\${1}" = "pre" ]; then
    rfkill block bluetooth
elif [ "\${1}" = "post" ]; then
    rfkill unblock bluetooth
fi
EOF
chmod 755 /lib/systemd/system-sleep/rfkill-bluetooth-workaround

for more information see this bug

S2 Idle Sleep

This may be irrellevant with kernel update for 18.04 Bionic and 19.04 Disco https://bugs.launchpad.net/ubuntu/+source/linux/+bug957