My Deepin install has been working well, but lately it doesn't want to suspend, regardless of the settings. This makes me nervous, not knowing what my computer is doing, if I walk away and forget to shut down. What could be causing this? I know that Deepin updates very slowly, so one possibility is that it's gathering info for an update, but so far I haven't seen one pending. Any other possibilities?

what is it doing instead of suspending?
does the screen blank after some time? does it lock? does it hibernate? or nothing at all, screen always on?

Nothing at all, screen always on. Just hanging out.

ok, try this command:
it should switch the screen off immediately, until you wiggle your mouse or press a key.
if that command makes it only flicker briefly (i.e. screen comes back on by itself) i'd say it's a desktop environment issue.
if that command doesn't even make it flicker, nothing at all, i'd say you have a deeper problem; acpi related maybe; maybe a new kernel version can help.

so:
- machine specs please; combine them into a search, adding keywords like ubuntu, screen won't suspend, acpi, ... try different searches. refine your searches.

- kernel version?

Deepin is now suspending ok. I ran an update and that seems to have solved it.