HPET <High Precision Event Timer> at Tyan H2000M (S3992-E) south-bridge

[d_elbracht]

just some info that may save somebody else time on that.

I swapped motherbards today on FreeBSD 6.2, AMD64,  cvsup'd 07/18/2007

Orignal was a Tyan K8S (S2882)
New is a Tyan H2000M (S3992-E)

on boot, the system got stuck right before it would mount drives.
A ctrl+c after waiting for a minute showed it hang somehere in /sbin/devd
It continued to the login prompt, but the timer (e.g. date) never increased

comparing the boot-logs showed: 
<K8S>
Timecounter "HPET" frequency 14318180 Hz quality 2000
acpi0: Power Button (fixed)
Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000

<H2000M>
acpi_hpet0: <High Precision Event Timer> iomem 0xfed00000-0xfed03fff on
acpi0
Timecounter "HPET" frequency 232831 Hz quality 2000

digging thru CVSUP, I  found the change in acpi_hpet.c
cvsup to 6.3-PRE, make kernel, and the problem seems to be gone:

<H2000M>
Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
acpi_timer0: <32-bit timer at 3.579545MHz> port 0x508-0x50b on acpi0
....
acpi_hpet0: <High Precision Event Timer> iomem 0xfed00000-0xfed03fff on
acpi0
acpi_hpet0: HPET never increments, disabling
device_attach: acpi_hpet0 attach returned 6

By accident, I found that the bios-default for HPET setable in the
south-bridge of the H2000M is DISABLED. Enableing it, the logs shows:
<H2000M>
Timecounter "ACPI-safe" frequency 3579545 Hz quality 850
acpi_timer0: <32-bit timer at 3.579545MHz> port 0x508-0x50b on acpi0
acpi_hpet0: <High Precision Event Timer> iomem 0xfed00000-0xfed003ff on
acpi0
Timecounter "HPET" frequency 14318180 Hz quality 900

looks like the simple problem in this case may have been (dam..d)
bios-setting

Dieter