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Date:      Sun, 29 Jul 2001 22:49:10 -0700
From:      Mike Smith <msmith@freebsd.org>
To:        Bruce Evans <bde@zeta.org.au>
Cc:        Daniel Rock <D.Rock@t-online.de>, current@FreeBSD.ORG
Subject:   Re: ACPI: Clock problems in -current 
Message-ID:  <200107300549.f6U5nAr02533@mass.dis.org>
In-Reply-To: Your message of "Sun, 29 Jul 2001 17:20:27 %2B1000." <Pine.BSF.4.21.0107291708130.1077-100000@besplex.bde.org> 

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> On Sat, 28 Jul 2001, Mike Smith wrote:
> 
> > You could also try building a kernel with CLK_CALIBRATION_LOOP defined
> > and then booting with -v (without the timer disabled).  This might be 
> > instructive (I don't know for certain that it'll calibrate the ACPI 
> > timer, since it may not have been probed yet).
> 
> It won't.  CLK_CALIBRATION_LOOP only iterates calibration of the i8254
> and TSC timers relative to the RTC.  None of the clock calibration stuff
> is very useful.  All the clock frequencies depend on the temperature,
> so their values at boot time are only slightly more related to their
> values at run time than their values at a random time.  Average values
> are probably better than boot time values.

Understsood, however the current problem reports indicate an off-by-2x 
problem, which the calibration loops would deal with just fine.

Unfortunately, I can't reproduce the problem here - the new timer seems 
to be working just fine.  Can anyone seeing this please let me know:

 - What power management hardware your system has: look at the output of
   pciconf -lv for a "power management controller", eg:

none0@pci0:7:3: class=0x068000 card=0x00000000 chip=0x71138086 rev=0x03 hdr=0x00    vendor   = 'Intel Corporation'
    device   = '82371AB PIIX4 Power Management Controller'
    class    = bridge
    subclass = PCI-unknown

 - which timecounter is in use on your system, eg:

mass# sysctl kern.timecounter.hardware
kern.timecounter.hardware: ACPI

 - whether you are seeing any "*time went backwards" console messages.

Thanks.
Mike

-- 
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also.  But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view.  [Dr. Fritz Todt]
           V I C T O R Y   N O T   V E N G E A N C E



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