[ltp] 600E battery under apmd

[Dale Chayes]

On Tue, 2002-01-08 at 08:44, Derek Harding wrote:
> Running SuSE 7.3 - kernel 2.4.10 - KDE 2.
> I wonder if any of you folk can tell me why my battery seems to go from 86% 
> to 5% in a matter of seconds yet the battery is actually fine and recharging 
> is too quick for it to actually be low. If I use the add-on battery in the cd 
> slot it goes on for ever. Is it a solution to disable the apmd and run on 
> trust and watch-keeping?
> ....

Hmmm,

I found a similar problem (RH 7.2 - updated to kernel 2.4.7-13 on my X20
using gnome if that matters.)  I also had serious instability problems
with suspend/resume.

I made a new kernel with one change in the apmd section of `make
menuconfig`  I changed "allow interrupts during APM BIOS calls" from NO
to YES 

and life got signficantly better. 

I was impressed to note that in the "HELP" section there is a
fascinating clue from those who know more about this than I:
 
======begin quote =====
CONFIG_APM_ALLOW_INTS:                                                  
Normally we disable external interrupts while we are making calls to
the APM BIOS as a measure to lessen the effects of a badly behaving
BIOS implementation.  The BIOS should reenable interrupts if it        
needs to.  Unfortunately, some BIOSes do not -- especially those in    
many of the newer IBM Thinkpads.  If you experience hangs when you     
suspend, try setting this to Y.  Otherwise, say N.                     
========= end quote ========
                                                 
I suspect that this may be BIOS-version dependent among other things.

-Dale

-- 
Dale Chayes <dale@ldeo.columbia.edu>
Lamont-Doherty Earth Observatory of Columbia University
V: 845-365-8434     F: 845-359-6940


----- The Linux ThinkPad mailing list -----
The linux-thinkpad mailing list home page is at:
http://www.bm-soft.com/~bm/tp_mailing.html