Comment 15 for bug 1825636

Recently bought an L390 Thinkpad and noticed the battery drain when suspended. Checked the syslog and observed the same issue you've reported. Just tried it out on several other laptops, as well as a desktop lying around in the office. Can confirm that this issue affects all of them. Here's a list:

Lenovo Thinkpad L390 (non-Yoga) running Debian 10.1 (buster) with MATE on kernel 4.19.0-6-amd64
Lenovo Ideapad 500-15ISK running Debian 10.0 (buster) with MATE on kernel 4.19.0-5-amd64
Asus UX310U running Ubuntu 18.04.3 LTS with GNOME on kernel 4.15.0-58-amd64
Desktop with an i7-4790K running Debian 10.1 (buster) with MATE on kernel 4.19.0-6-amd64

I've measured the battery drain rate on the L390 to be around 1-2% every hour of suspend. There is a large thread on the Linux Lenovo forum, where they're discussing a similar issue (battery drain when sleeping) with the X1 Carbon, though they came to the conclusion that the laptop itself doesn't support deep sleep (ACPI S3 sleep), with Lenovo instead opting for s2idle (ACPI S0 sleep). The L390, however, does report it supports S3 sleep, so it's possible the issue is unrelated.