acpi_cpu_idle panic (Was: Re: kernel panic with todays source)

Eric Anderson anderson at
Wed Nov 19 14:51:21 PST 2003

Nate Lawson wrote:

>On Tue, 18 Nov 2003, Eric Anderson wrote:
>>Nate Lawson wrote:
>>>cvsup to -current as of today would be a good first start.  The code was
>>>committed Nov 15.  Then boot with acpi enabled and post the output of
>>>sysctl hw.acpi.cpu.  You can try different levels by doing sysctl
>>>hw.acpi.cpu.cx_lowest=x where x is 0...(number_supported_states - 1)
>>Thanks! I've rebuilt and am happy to say that nothing is hosed and I
>>booted successfully :)
>>Here's my sysctl output:
>>$ sysctl hw.acpi.cpu
>>hw.acpi.cpu.max_speed: 8
>>hw.acpi.cpu.current_speed: 4
>>hw.acpi.cpu.performance_speed: 8
>>hw.acpi.cpu.economy_speed: 4
>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%".

>>hw.acpi.cpu.cx_supported: C1/1 C2/1 C3/85 C3/185
>>hw.acpi.cpu.cx_lowest: 0
>>hw.acpi.cpu.cx_history: 23589/0 0/0 0/0 0/0
>>I played with the different levels a bit, and can't tell much difference
>>in them. Let me know what else I can try to break with this.  Just for
>>the info, I booted with a/c plugged in, but did the sysctl running on
>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? 

>>Eric Anderson	   Systems Administrator      Centaur Technology
>Say hi to Tom Crispin for me.  :)
He says "hi" :)   (small world, eh?)

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).

Thanks for the great work!

Eric Anderson	   Systems Administrator      Centaur Technology
All generalizations are false, including this one.

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