m1 mbp 14" with LG ultrafine 5k not sleeping

[rieuk]

I recently got the LG ultrafine 5k to pair with the m1 mbp 14 inch. However, I notice that when connected, and using it in clamshell mode, I send the machine to sleep, the monitor goes off. And I'm not sure what the laptop display is doing since it's closed. But I assumed it was asleep. I come back in the morning to notice that the laptop is running warm. Which means it's been awake.

How can I diagnose what's going on? What logs do I look at, and is this normal? How can I send it to sleep from clamshell mode and make sure it stays there overnight? Is disconnecting the monitor and all peripherals every time the only option?

 

[rieuk]

*bump* anyone got any ideas?

 

[solouki]

Hi rieuk,

While in sleep mode, your MBP may be configured to wake for any number or reasons, say "Wake for network access" as an example. There are many other possibilities, such as the waking to perform OS cleanup, indexing, or security updates. In any case, you may find the Terminal command "pmset" of use to you for ferreting out if some utility or app is preventing your computer from entering sleep mode. For instance,

pmset -g

will show you the various current power settings. For instance, the "hibernatemode" should probably be "3" for your laptop. If you'd like to see what assertions will limit sleep, then

pmset -g assertions

or

pmset -g assertionslog

will let you know if some app is keeping your laptop from entering sleep mode.

For example, if you execute the following Terminal commands:

caffeinate -ims &
pmset -g assertionslog

you will see that the "caffeinate" utility is preventing your laptop from entering sleep mode "forever". You can then halt the "caffeinate" process by executing:

kill -9 %1
pmset -g assertionslog

to find that "caffeinate" is no longer preventing your laptop from entering sleep mode.
If you wish to alter some power setting, then you must be "root", that is, you must use "sudo".

Good luck,
Solouki