acpi_cpu

Nate Lawson nate at root.org
Fri Nov 21 10:57:06 PST 2003


On Wed, 19 Nov 2003, Eric Anderson wrote:
> Nate Lawson wrote:
> >You should run a benchmark with different values for
> >hw.acpi.cpu.current_speed to be sure the throttling control still works
> >ok.  I left it mostly intact so you shouldn't see any problems but it's
> >still good to test.  As you change it, you should see dmesg output of
> >"acpi_cpu0: set speed to xx%"
>
> I can change the hw.acpi.cpu.economy_speed value, but the current_speed
> is read only.   When I set economy speed, it automatically bumps the
> current speed down to my economy value (as expected).  However, no dmesg
> output.  The only note I see is when going from AC to battery, I get:
> kernel: system power profile changed to 'economy'
> and of course going back to aAC shows 'performance' instead of economy.
> I never see any "set speed to xx%".

That is correct behavior.  The printf is either under bootverbose or an
ACPI debugging print so you won't see it normally.

> >You should set hw.acpi.cpu.cx_lowest to 1 regularly and 2 or 3 if you're
> >using battery.  This will save on heat.  I'd also be interested in if
> >you'd set it to 3 while on battery and run a typical workload for an hour
> >and then send me the result of sysctl hw.acpi.cpu.  The cx_history value
> >helps me know if my scheduler is accurate.
>
> I'll try this tomorrow - anyway to get it to automatically set it to a
> value when going in to economy mode?

Not yet, but working on a generalized way to program a variety of settings
for economy/performance mode based on devd.

> On a side note - can I do anything with the "lid control switch" acpi
> piece?  I'd like to make it turn off the screen and go into a sleep
> mode  (it goes into sleep, but the screen stays lit up).

ACPI events now are accessible through devd.  So if you look at
/etc/*mumble*/devd.conf, you can see an example for getting the lid switch
state.

However, the more direct way to do this is via sysctl
hw.acpi.lid_switch_state=S3 (or whatever state you want the laptop to go
into when you close the lid).  Please test the desired state manually with
acpiconf before enabling it by default.  Much of our suspend/resume
support is still incomplete.

-Nate


More information about the freebsd-current mailing list