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Re: regression (crash) in sysmon/acpiacad

On Thu, Feb 04, 2010 at 10:15:03PM +0100, Matthias Drochner wrote:
> said:
> > Since the charge value was not updating, it  might be that the ACPI
> > Notify isn't working here.

Since this involved running on battery power, I doubt it is about the
removal of the refresh routine in acpiacad(4). If the sensor value changes
when one plugs/unplugs the AC, it is easily verified to be working.

> For the critical shutdown, a call to _BTP might help.

The _BTP is just a custom warning trip-point that triggers a Notify once
reached. It is probably there to provide user space applications some
control over the limits, and to possibly avoid polling of the values.

Note though that nothing has changed in acpibat(4) with regards to the
refresh routine or the sensors generally.

> But anyway, from my limited experience with process control
> ("SCADA") systems, it makes sense to maintain a timestamp
> for the last data value read (or delivered by asynchronous
> notification) and force a fresh read if it is older than
> a limit defined by the provider (and possibly overridden
> by the consumer).

Something like is already done in acpibat(4).

- Jukka.

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