Re: slow clock on DELL Latitude 5501

[is%netbsd.org@localhost]

Frank K. suggested:

> TSC running at 10GHz on a 2.5GHz CPU looks a bit strange to me.
> Try another timecounter, those frequencies look more like the ones
> I am used to. Some is probaly wrong with the frquency estimation code
> for TSC.

I had thought of that, but didn't help. En detail:

I have nearly always about 4 seconds between "sleep 1", but with
some timecounters, displayed time (as of  "date") progresses not
in 1 seconds, but in 4 second steps.

		sleep 1		date
		duration	increment
--------------------------------------------
TSC		~4 sec.		1 sec.
clockinterupt	~4 sec.		1 sec.
lapic		~4 sec.		1 sec.
ACPI-Fast	~4 sec.		4-5 sec.
hpet0		~4 sec.		4-5 sec.
i8254		very long	?
dummy		very long	?
--------------------------------------------

for the 8.1 kernel, the difference seems to be that on i8254 and
dummy sleep 1 takes 4 seconds, but the time doesn't progress:

--------------------------------------------
TSC		~4 sec.		1 sec.
clockinterupt	~4 sec.		1 sec.
lapic		~4 sec.		1 sec.
hpet0		~4 sec.		4-5 sec.
ACPI-Fast	~4 sec.		4-5 sec.
i8254		~4 sec.		<0.03 sec.
dummy		~4 sec.		<0.03 sec.
--------------------------------------------

is writing 

sysctl -w kern.timecounter.hardware=...

the right method to switch, or do I need to disable
the TSC one by userconf when booting to make the clock
interupt use different hardware?

	-is