PROBLEM: Linux system clock is running 3x too fast

From: Fast Clock
Date: Sun Aug 22 2004 - 23:07:10 EST


My Athlon 64 laptop (HP Pavilion zv5000z) dual-boots Linux and Windows
XP. The Windows system clock is running accurately but the Linux system
clock is running 3 times too fast.

The problem occurs in all of the Linux distributions and releases that
I've tried, including Suse 9.1, Fedora Core 1 & 2, kernel versions
2.4.x, 2.6.x (up to 2.6.8-1.521), 32-bit & 64-bit releases.

The Linux system clock problem is also intermittent. Approximately 1 of
10 (cold) boots could yield an accurately running Linux system clock...
I've tried kernel boot options "clock=tsc", "clock=pit", "clock=pmtmr"
and have seen about the same 1/10 (failed/passed) ratio for each of
them. I've also tried kernel boot options "acpi=on" & "acpi=off" but
they don't seem to have any affect on the problem.

The differences in dmesg outputs between "good" and "bad" boots are as
followed.

good: time.c: Detected 797.952 MHz processor.
bad: time.c: Detected 265.995 MHz processor.

good: Calibrating delay loop... 1576.96 BogoMIPS
bad: Calibrating delay loop... 516.09 BogoMIPS

good: Detected 12.468 MHz APIC timer.
bad: Detected 4.156 MHz APIC timer.

good: intel8x0_measure_ac97_clock: measured 49383 usecs
intel8x0: clocking to 47408
bad: intel8x0_measure_ac97_clock: measured 48347 usecs
intel8x0: measured clock 16547 rejected
intel8x0: clocking to 48000

Full dmesg logs (goods and bads) are available upon request.

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