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Re: slow clock on Dell I8k1

On Thu, Feb 07, 2002 at 12:22:26PM +0100, Hein Roehrig wrote:
> on my Dell Inspiron 8100 the clock loses several minutes per hour 
> --- so much in fact that ntp doesn't work properly. I tried to find 
> out whether something in my (pretty much standard woody) setup 
> interferes with the clock, but haven't found anything (in 
> particular, hwclock --adjust is *not* called.)
> Any hints? Also, I have not yet figured out how to make ntpd more 
> lenient about a bad local clock. If anybody knows from the top of 
> their head how to get rid of the "synchronization lost" messages, I 
> would be grateful for a hint.

Disable all battery monitors. Battery monitors read /proc/apm, which
triggers the kernel to call the APM BIOS. The BIOS will switch the CPU
to System Management Mode in which it slowly polls the batteries for
their amount of charge left. System Management Mode is usually entered
with interrupts disabled so the kernel will loose a couple of timer
ticks which causes the real time clock to run slowly. Other symptoms
are garbled sound and lost characters on RS232 interfaces.


J.A.K. (Erik) Mouw, Information and Communication Theory Group, Faculty
of Information Technology and Systems, Delft University of Technology,
PO BOX 5031, 2600 GA Delft, The Netherlands  Phone: +31-15-2783635
Fax: +31-15-2781843  Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/

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