bug#57052: elogind-service specifies a variable that's ignored by defualt

[bokr]

Hi Liliana,

On +2022-08-08 12:45:10 +0200, Liliana Marie Prikler wrote:
> Am Sonntag, dem 07.08.2022 um 23:29 +0000 schrieb Cairn:
> > "HandleLidSwitchExternalPower= is completely ignored by default (for
> > backwards compatibility)"[1]
> > 
> > I noticed (with help in IRC) that my laptop wasn't suspending on lid
> > close when plugged in and charging, which I hadn't seen happen on
> > other systems. I now know that I can set this by configuring the
> > `elogind-service` parameter `handle-lid-switch-external-power`.
> > Regardless, it seems like it should default to being unset rather
> > than set/ignored, since that would heed the line I quoted above.
> I think you're misreading that line.  What it states is not that
> "HandleLidSwitchExternalPower" is ignored by default, but
> "HandleLidSwitchExternalPower=" is ignored by default, i.e. there will
> be no value unless one was provided (whichever semantics "no value" has
> later on) is only confusingly explained later on.
> 
> IMHO the Guix behaviour of always setting a value is the right one
> (explicit is better than implicit after all).  As for the default
> values, one might disagree as to which fits, but I don't think ignoring
> lid switches while powered is harmful.
>

What would you advise if there's no battery power,
or for some reason one is running on plug power only,
for worriers that the bulding power might fail?

I'd guess a power brick would power for some milliseconds 
and wonder if this is detectable, i.e., to do something
at least to leave a goodbye world message somewhere if the machine
was not suspended with sufficient state to resume after power restore?

Buy a UPS, and don't go away long enough for that to run out? :)

> Cheers
> 
--
Regards,
Bengt Richter