[Discuss] Suspend is Great…When it Sticks

[kentborg at borg.org (Kent Borg)]

My current Linux computer, like the one before it, isn't very good at 
staying asleep. Configuring it to sleep when the lid closes does work, 
but it is the event of *closing* the lid that does it, not the static 
state of *being* closed. And it seems something or other can wake it. 
While the lid is still closed. No one is closing the lid (it is closed, 
in my carry on, under the seat in front of me), so there is no event to 
trigger another suspend.

So I wrote a trivial little (Rust) program: "sleep-dammit".

It looks at the lid state and if closed, it tells systemd to suspend, 
and it does that in an infinite loop. The loop also has a 10-second 
thread sleep, so a bug won't put my in an aggressively narcoleptic 
battle. It prints a time stamped message saying it is suspending. And 
when the lid is open it also prints a time stamped message, but only 
every 60 times through the loop.

Mostly I don't want the computer to sleep when the lid is closed, so I 
expect I mostly won't run this program. But when I do grab it as I go 
out and about, I can choose run sleep-dammit.

No, I didn't write some fancy stateful program that does cool stuff over 
D-bus. Someone already did that, and it doesn't work. So I wrote 
something really simple and manual: If the program is running and the 
lid is closed, suspend.


Today I was out on some errands and I carried my computer with me, as a 
test. This is the output I saw when I got back home:

> lid open at Tue Nov 19 17:36:44 2024.
> lid closed, but if we hit this code we are running, so suspend at Tue 
> Nov 19 17:38:14 2024.
> lid closed, but if we hit this code we are running, so suspend at Tue 
> Nov 19 17:57:03 2024.
> lid closed, but if we hit this code we are running, so suspend at Tue 
> Nov 19 18:24:45 2024.
> lid closed, but if we hit this code we are running, so suspend at Tue 
> Nov 19 18:50:54 2024.
> lid closed, but if we hit this code we are running, so suspend at Tue 
> Nov 19 18:52:38 2024.
> lid closed, but if we hit this code we are running, so suspend at Tue 
> Nov 19 19:02:07 2024.
> lid open at Tue Nov 19 19:55:41 2024.

It woke up 5 spurious times while was out!


-kb


P.S. Is this something I can blame systemd for? No? Well, it was worth 
the try.