Problems with hw.acpi.cpu.cx_lowest=C2 (Re: cvs commit: src/etc/defaults rc.conf)

Kris Kennaway kris at
Mon Mar 13 17:25:25 UTC 2006

On Mon, Mar 13, 2006 at 09:03:35AM -0800, Nate Lawson wrote:

> >I finally managed to test this in RELENG_6.  The system performance is
> >not obviously bad, but sound playback is distorted (e.g. the 'bell' in
> >KDE is much higher pitched than it should be, and on the console it is
> >low pitched and lasting about 3 seconds).  Nothing is logged on
> >console.
> >
> >There may be other problems that I didn't notice right away, but the
> >sound problems were enough to make me turn it off again.
> Are you sure that's the cause?  (Does setting cx_lowest to C1 fix it?) 

Absolutely sure: the system worked at C1 after boot, then I set it to
C2, observed that beeping was broken, then set it back to C1 and
observed that it worked again.

> Can you send the output of sysctl hw.acpi so we can see how often each 
> cx type is being run?

# sysctl hw.acpi
hw.acpi.supported_sleep_state: S1 S3 S4 S5
hw.acpi.power_button_state: S5
hw.acpi.sleep_button_state: S1
hw.acpi.lid_switch_state: NONE
hw.acpi.standby_state: S1
hw.acpi.suspend_state: S3
hw.acpi.sleep_delay: 1
hw.acpi.s4bios: 0
hw.acpi.verbose: 0
hw.acpi.reset_video: 1
hw.acpi.cpu.cx_supported: C1/0 C2/1
hw.acpi.cpu.cx_lowest: C1
hw.acpi.cpu.cx_usage: 100.00% 0.00%
hw.acpi.thermal.min_runtime: 0
hw.acpi.thermal.polling_rate: 10
hw.acpi.thermal.tz0.temperature: 38.0C -1
hw.acpi.thermal.tz0.passive_cooling: 0
hw.acpi.thermal.tz0.thermal_flags: 0
hw.acpi.thermal.tz0._PSV: -1
hw.acpi.thermal.tz0._HOT: -1
hw.acpi.thermal.tz0._CRT: 75.0C
hw.acpi.thermal.tz0._ACx: 50.0C -1 -1 -1 -1 -1 -1 -1 -1 -1

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