On 09/17/08 07:44, Li, Aubrey wrote:
> Bill.Holler wrote:
>
>   
>> On 09/16/08 16:32, Li, Aubrey wrote:
>>     
>>> Hi Bill,
>>>
>>> Bill.Holler wrote:
>>>
>>>
>>>       
>>>> Hi Aubrey,
>>>>
>>>> My test machine has the same problem with the new push.
>>>>
>>>> The problem was a miss-merge; sorry it was probably my fault.  :-(
>>>> The promotion code can promote passed the end of the cstate list.
>>>>
>>>> The promotion code at the end of cpu_acpi_idle():
>>>>        if ((cs_type < cpu_max_cstates) && (delta >
>>>>                cstate->promotion)) mcpu->mcpu_idle_type++;
>>>>
>>>> cs_type can be decremented allowing mcpu->mcpu_idle_type to
>>>>         overflow. /* * OSPM uses the BM_STS bit to determine the
>>>> power state to enter 
>>>>         * when considering a transition to or from the C2/C3 power
>>>> state. 
>>>>         * if C3 is determined, bus master activity demotes
>>>> the power state
>>>>         * to C2.
>>>>         */
>>>>        if ((cs_type >= CPU_ACPI_C3) && cpu_acpi_bm_sts())
>>>>                cs_type = CPU_ACPI_C2;
>>>>
>>>>
>>>>
>>>>
>>>>         
>>> It's not a miss-merge, It looks like a promotion bug.
>>> Thanks to fix it. So, is your system working okay with C4 or the
>>> second C3? 
>>>
>>>       
>> Yes, my system is working great with the second C3.  :-)
>>
>>
>> My initial thoughts on duplicate C-States are: we should keep
>> duplicate C-States.  Does that sound reasonable?
>>
>> Is it possible to list the proper C-State for duplicate C-States?
>> For example can a duplicate C3 be listed as C3 instead of C4?
>> Will the current_cstate field of cpu_info kstat be able to
>> distinguish duplicate C-States? 
>>
>>     
> I failed to find the mail. But if I recall correctly, Mark mentioned
> some
> boxes with the buggy BIOS could have a few entries are the same.
> Since we don't know how BIOS implementation the _CST object, 
> I think the current implentation may be more reasonable.
>
> Thanks,
> -Aubrey
> _______________________________________________
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> tesla-dev at opensolaris.org
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>   

I remember a bug Mark worked on with P-States.  Buggy BIOS
could create bad duplicate _PSS P-State ACPI object.
The duplicate objects contained zeros?
I agree we should ignore duplicate _CST objects until they
prove to be stable.

Thank you,
Bill

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