Subject: elogind's suspend-then-hibernate requires dmi-sysfs to detect wakeup type

From: Josselin Poiret <[email-masked]>
Date: Thu, 24 Apr 2025 16:56:29 +0200

Hello everyone,

The suspend-then-hibernate option of elogind tries to detect the type of
wakeup that the system supports, and to that end reads
/sys/firmware/dmi/entries/1-0/raw.  However that file only exists if
the kernel module dmi-sysfs has been loaded, which doesn't seem to be
the case by default on my Guix system.

If that doesn't work out, it falls back to a custom implementation that
wakes up the system periodically to check the battery status, however
that is also broken for some other reason™ on my system, leading to an
instant hibernation.

Loading dmi-sysfs manually solves this issue, but I don't know how to do
that with the elogind-service-type implementation.

Best,
-- 
Josselin Poiret