Re: [tlug] Suspend on ThinkPad X1 Carbon

[Furkan Mustafa <furkan@example.com>]

I am also curious,

> Suspend sometimes works when I close the lid, but sometimes not
What is your observation when it does not work? And what do you use for 
sleep, upower &/ elogind ?

So depending on the power management software, it is possible that the 
computer actually goes to sleep once, but wakes up at some point, (due 
to some other magnetic thing coming close-by, triggering the lid 
switch), and stays awake... Although a more careful implementation, 
would keep probing lid status post-wakeup, and put it back into sleep if 
it wasn't supposed to wake up now.

I was using a simple stupid script with acpi-eventd to lock screen and 
put laptop into sleep on lid close.. it was naive, and many times the 
laptop got burning hot in my backpack.

Some lid sensors are magnetic, and prune to interference by other things.
Eg. Solution: put your tablet with magnets on all its corners and sides 
away from a sleeping laptop. (or fix the software)

There are other wakeup events as well, some USB controllers are waking 
up CPU from time to time, some charge controllers wake up CPU on charge 
state change or on low charge, .. on one of my laptops I had to disable 
XHC (USB3 controller?) from wakeup sources. (it's easy)

Another example would be Pinephone, it's buttons are too sensitive, very 
easy to click in your pocket.. but a clever software would check the ear 
proximity sensor and/or light sensor as well, just to make sure.

I would also keep an open eye for other reasons, this could be happening 
regardless of lid or manual-lock&suspend, it might be a coincidence. 
Sometimes things like network file systems unintentionally block suspend 
as well. Or a buggy device driver. For debugging that, I usually open up 
a terminal, spawn various log tails ( `dmesg -w`, `tail -F 
/var/log/messages`, `journalctl -xn -f`, whatever you have ).. and try 
closing the lid, wait a bit, open it back again, see what you have in logs..

Don't know if any of above is relevant, but I had such cases, so I hope 
it might be helpful.

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Furkan Mustafa
https://rainlab.co.jp