Mailinglist Archive: opensuse (946 mails)

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Re: [opensuse] logrotate
On 2017-09-16 08:05, Per Jessen wrote:
John Andersen wrote:

Side note: systemd timers will allegedly wake a machine up from
suspend so that it can run some task and then suspend it again.

Sounds more like a BIOS feature, I'm sure I've seen or read of that.

Haven't tested this yet.
https://cmcenroe.me/2014/11/24/scheduled-suspend-and-resume-with-systemd.html

Hmm, how does that work ? If the machine is suspended, how can anything
run?

The BIOS can program the CMOS clock chip (I think it is that one, it has
its own battery) to wake up the board. You need support from the board
and the power supply. Ie, the power supply has to be supplying some
power to the board continuously, and I think it has a line that signals
the PSU to go to full power on request from the board.

It is an interesting feature, but has dangers. I think Windows 10 uses
it: the machine can wake itself and run automatic updates. If it is a
laptop on battery it of course depletes the battery (a bit or a lot). If
the laptop is inside a bag it can heat up tremendously.

Android uses it a lot. Often I find the battery totally depleted because
some app wanted to do something and failed ("pocket" usually).

--
Cheers / Saludos,

Carlos E. R.
(from 42.2 x86_64 "Malachite" at Telcontar)

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