Re: end-user support: Battery alarm

[Rich Townsend <rhdt-OBnUx95tOyn10jlvfTC4gA@public.gmane.org>]

Mirko Hessel-von Molo wrote:
> Dear all, 
> 
> I have a probably stupid question for which I couldn't find the 
> answer anywhere else. 
> 
> Is it true that a 'battery' event is raised by the kernel when the 
> 'current capacity' given in /proc/acpi/battery/BAT0/state goes below 
> the limit defined in /proc/acpi/battery/BAT0/alarm?
> 
> I'm trying to use the battery alarm to make my system warn the user
> and shutdown, if necessary. 
> 
> My setup is the following: I'm using a Dell Latitude D800 with BIOS A07,
> running under Linux with Kernel 2.6.7 (not the latest one, I know).
> As I 'organically evolved' the system from a RedHat 7.3 base install,
> I'm reluctant to upgrade to some distro which provides acpi support. 
> 
> So far, I got pretty much everything to work, ac_adapter and battery events
> are raised when the power supply changes. However, no event is 
> raised when the battery capacity goes below the warn level. I can't remember
> where I have read this, but somehow I got the idea that this should be the
> case.
> 
> Does anyone have an idea where my problem could be?
> 

Yes; I've no doubt that this is due to a broken DSDT. Unless Dell has 
put something in the DSDT that causes periodic polling of the battery 
level, there is no way a notification will be sent when the battery 
passes the trip point. There is certainly nothing in the Linux kernel 
that handles the polling.

cheers,

Rich


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