On 2015-07-01, Christopher Sean Hilton <[email protected]> wrote:

>> Regarding the net4801, CPU_SOEKRIS and CPU_ELAN_* only appear to
>> concern the GPIO port, so if you don't hook up anything there, my
>> best guess is that a standard install with GENERIC should work just
>> fine.
>
> The net4801 is supposed to be perfect as an inexpensive gps driven
> clock for ntpd. But I thought that having CPU_ELAN and CPU_ELAN_PPS in
> the kernel added precision to the timekeeping?

Looking again, I see that it's the net4501 that is based on the AMD
ElanSC520.  The net4801 has an NSC SC1100 and is thus completely
unaffected by CPU_ELAN_*.

FreeBSD's special Elan support is concentrated in a single file,
sys/i386/i386/elan-mmcr.c:
https://svnweb.freebsd.org/base/stable/10/sys/i386/i386/elan-mmcr.c?view=log

CPU_ELAN_PPS is only of interest if you want to precisely timestamp
a PPS signal on a GPIO pin.  CPU_ELAN_XTAL is for people who want
to run the CPU from a different clock.  CPU_ELAN just pulls in the
support for the other CPU_ELAN_* defines.

-- 
Christian "naddy" Weisgerber                          [email protected]
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