No battery critical warning on Thinkpad t42

[Nate Lawson]

m.ehinger at ltur.de wrote:
> i recognized that an my Thinkpad T42 i get no battery critical warnings! All i get is a battery low state.

There is no guarantee that a given system generates critical warnings. 
It may be that your BIOS doesn't implement this.

> hw.acpi.battery.state becomes 1 at discharge, 2 at recharge and 0 at full.

Those are correct.

> I get ACPI notifies from CMBAT at 4% and 38%  with hw.acpi.battery.state: 1 and at 100% with hw.acpi.battery.state=0.
> 
> Is that the correct behaviour?

These doesn't seem to be anything wrong there.  The battery is free to 
generate notifies whenever something has changed.  The BIOS may have set 
trip points for those levels.

> Is there an default action when battery becomes critical?

No, just prints a message on console.  We could initiate shutdown or 
suspend, but there are too many systems that report "critical" early or 
incorrectly.  Also, a lot of systems don't resume properly so suspend 
isn't a good route either.

-- 
Nate