system clock going backward

[Jay Cliburn]

Jay Cliburn wrote:
> Ali Sobhi wrote:
>> Folks,
>> I'm facing a strange situation on my systems running FC5 and my 
>> research has resulted in some information which I'm not about.
>> I've to mention that this problem showed up with FC5 and was not there 
>> when FC4 was running.
>>
>> The system clock is misbehaving and sometimes goes backward. No ntpd 
>> running (read on)
> [snip]
>> where should I go from here?
>> should I disable "acpid"?
>> should I use "pmtmr_good" boot parameter?
>> should I disable power management functions of the BIOS? (this is 
>> desktop model)
>> which log file to look at to figure out what is going on?
> 
> I picked up a surplus IBM Net Vista 8308 last week (ICH4/82801DB 
> chipset), and lo and behold, I saw the same clock weirdness you 
> reported.  There's a smattering of similar reports on the web spread 
> across all distros.  The best description of the issue is in the source 
> code itself.  Take a look at the file arch/i386/kernel/timers/timer_pm.c.
> 
> It seems to keep time okay if I boot with noapic, but I'm trying a 
> different option at the moment:  clock=tsc.  I'll let you know if it 
> works out.

It's been about 24 hours now; long enough to say that booting with clock=tsc 
results in proper timekeeping on the system.