HP/Compaq nx6325 clock "jumping around"

[Bruce Evans]

On Sat, 5 Jul 2008, Peter Jeremy wrote:

> On 2008-Jul-03 15:55:28 +1000, Bruce Evans <brde at optusnet.com.au> wrote:
>> - pressing the lid switch to turn the screen off makes the time jump by
>>   almost precisely 1 second using any timecounter.  The system appears
>>   to spend the 1 second in something like SMM mode with all interrupts
>>   and all timecounters stopped.  More precisely, the jump is:
>>   ACPI-fast and TSC: -1.000000 +- 10 uS
>>   i8254:             -1.043000 +- 1 mS
>
> My nx6125 with F.11 BIOS does something very similar but only in VTY
> mode - I don't see the time jump when running X (and I haven't tried
> measuring the jump to that accuracy).  Sometimes I see a time jump
> when switching between VTY and X.  Other than that, ntpd is quite
> happy with ACPI-fast.

You mentioned this a while ago.  I just tested it (again?).  The 1 second
jump was still there in X mode (old X).  There seemed to be a jump starting
X the first time, but not for restarts.  The 1 second jump sometimes caused
"calcru: runtime went backwards" messages.  I use "ntpdate -q <ntp-server>"
in a loop to measure jumps accurately (if they are isolated).  (This is
more accurate than ntptrace.)

Bruce