I have a 2020 Dell XPS that I installed Ubuntu 20.04 on (kernel 5.4.0-29-generic). I noticed that there was quite a lot of power drain when the laptop was suspended. I did some digging and realized that s2idle was the mem_sleep mode
brian:~$ cat /sys/power/mem_sleep
[s2idle] deep
To have less power consumption on sleep, I switched the mem_sleep mode to deep by creating a file: /etc/sysfs.d/mem_sleep.conf with the contents
power/mem_sleep = deep
I rebooted the laptop and checked the mem_sleep mode
brian:~$ cat /sys/power/mem_sleep
s2idle [deep]
However, when I closed the lid and re-opened it, I saw the Dell logo like it was booting up. The screen never changed - it just stayed on the Dell logo. This model of the Dell XPS has a feature where if the laptop is shutdown, it will boot when you open the lid. I thought that might somehow be interfering, so I turned that off in the bios. No dice.
I also noticed that when I connected the laptop to an external monitor, everything on the monitor was normal. I could login and use the computer, but the laptop screen still showed the Dell logo. I have to restart the laptop to get it to display anything other than the Dell logo, which defeats the purpose of suspending the laptop.
If I switch mem_sleep back to s2idle, it works fine.
Does anyone know what's up with this?
