ср, 5 февр. 2020 г. в 06:03, Stefan Monnier <monnier@iro.umontreal.ca>:

> >> No: `M-x battery` will emit the warning.
> > So `battery-upower` should check the correctness of the
> > `battery-upower-device` on every call?  It would make it heavier, but of
> > course more reliable, because user might change the value of the
> > `batter-upower-device` in runtime
> >
> > We might have `nil` values for the `battery-upower-device` and
> > `battery-upower-line-power-device` meaning "autodetect".  This will
> require
> > additional call to D-Bus (battery-upower-device-list) on every call to
> > `battery-upower`, probably this is OK.  If user want extra speed he just
> > set right values for that vars.  Sounds good?
>
> Right, we have to decouple the custom vars `battery-upower-device` and
> `battery-upower-line-power-device` from the actual list of devices.
> We can do this by recomputing the actual list (and checking its
> validity) every time time.
>
> Or if the performance impact matters, we can do this computation on the
> first call and then check every time that the custom vars haven't
> changed (and ask for D-Bus to calls us back when the list needs to be
> changed).
>

Not much impact actually.  Here is the updated battery.el against the
master this time.
Also added "%b" format-spec, so 'M-x display-battery-mode RET' shows "+" in
case AC is on-line

Thanks


-- 
lg